Every car I ever owned had nitrous kit on it.  I love my nitrous.  Here I will try to write as detailed as possible instructions on how to install Zex Nitrous Kit #82011 on Grand Prix GTP.  Hopefully this will give you an idea in what's involved in install.
	*Note: Could be out of date. This was written back in 2000 while installing it on my 1999 Grand Prix.
Step 1	My First step was to find place for ZEX Control Box.  Some people place it under their K&N open cone setup, others in front of their SLP cold air intake box, and some on side of their CAI box.  Since I have Thrasher CAI which takes a lot of room under hood I had to find a different place.  When finding place for your box please not the length of provided SS N2O line, its only 15' and GP is big car, keep that in mind.  Also nozzle feed line is only 6' so your box can't be far away from your TB.  I placed my box behind STB on firewall, but to get it there you need to remove engine hoist bracket, which you don't need until you want to pull your engine out.  Use 13mm wrench for two bolts holding the bracket.  This will also allow you to change spark plugs very fast.  Don't drill anything yet go to Step 2
Step 2	Now before bolting on your ZEX Box you want to make sure your N2O line is long enough.  So place one end of line where your box will be plus give it some breathing space and run it down the firewall next to fuel lines, continue running the line under car next to fuel lines (use zip ties)...  You will have to improvise after you get to gas tank, just place the line away from movable parts, don't let it hang and make sure its protected by other car parts...
Step 3	How do you get line in your trunk?  Well first decide where you want to place your bottle, some  people place it where their spare tire is and have spare tire fly around their truck.  I placed it on left side of my truck so it doesn't interfere with my stereo setup.  Note: If you place your ZEX box under cone line will not be long enough for you to place it where I placed mine.  After you make your decision its time to drill a hole in your trunk.  You need to drill a 3/4" hole, place a grommet, and run your line through it. If line is long enough you go to step 4 other wise rethink your box location, your bottle location and your line route.  Note: Grommet not in picture just some electrical tape... :)
Step 4	You could install your bottle at this point or Zex Control Box, I decided with box since I wanted to get everything under hood done first.  My next step was to install vacuum lines.  First you remove T tap from fuel pressure regulator, place a fitting (not provided, smallest size you can get see picture bellow), and attach one of the provided hoses on the fitting.  Next step is to install fuel jet on Zex box by selecting one of the provided jets and attaching it to "intake" fitting.  They also provided clamps but i had no need for them since it was so hard to get it on, i don't think a little pressure will pop it off.  next step is to attach other hose to Zex Box "regulator" and attach other end to fuel pressure regulator where T tap use to be.  Provided hoses where long enough for my setup but if you install your box under K&N or somewhere else they wont be long enough and you will have to buy new once. (see Feb. 04/2002 note below)
Step 5	Next we install N2O nozzle, first assemble it with jet you like.  Then decide where you going to place it.  At first I put mine in rubber intake, drilled a hole and placed it so it faces TB.  I used my own screws to hold jet in place and not provided once.  You can also get custom made TB spacers that you insert between your SC and TB, drill a hole in it and insert nozzle in it.  This turned out to be a be a bad place for jet, it didn't like it much, since then I moved jet closer to TB (its touching it now) and it worked better.  Spraying at location is OK and will work.  But some of that nitrous will hit your MAF sensor and will make it read off, or will make it read inconsistent, and it will confuse your PCM.  So my solution was to build my own TB to SC spacer out of 3/4" thick Polypropylene plastic, same as my alcohol injection spacer.  I purchased GM TB gasket and cut out plastic in same shape.  It also required longer M6 bolts(55mmx1mm) to replace short stock bolts that were holding TB to SC.  This worked like charm and I used it for as long as I had nitrous on my car.  If you want to make same thing contact me and I can get you some plastic cheap.
Step 6	Wiring is next, make sure you measure voltage of everything with digital voltmeter before installing it.  Black wire goes to ground (ofcourse) I got mine off STB bolts. Red wire goes through firewall (grommet) and connects to a big red switch that you get from ZEX, you will need some extra wire to reach inside of car.  Switch requires 12v at 15A, I found my source in fuse box (glove box), there was unused space with 20A(see picture).  White wire connects to your TPS middle wire, this is what triggers nitrous.  Follow ZEX instructions on how to program your TPS trigger.
Step 7	Bottle Install... What I thought would be easiest thing to do turned out to be hardest and longest.  My selected place for bottle was a bad one, it turns out car chassis goes right under my bottle place and my muffler is in the way of me reaching the bolts under car.  But that didn't stop me, I placed my bottle brackets so I don't drill into my cars frame, first hole was easy, second one was a bitch, I was drilling into my frame, and ended up braking my drill bit at 9:00pm when all stores are closed.  I just took a smaller bit and continued drilling all holes (I had to expand them a little).  Placed the screws and didn't bother going under car since the bolts them self were holding pretty good..  Also going through trunk carpet isn't easy...
Step 8	Now its time to try out if everything works.  Open the bottle up, make sure you don't have any N2O leaks (you will hear it if there is a leak), put your car in ON position, flip the N2O switch, and press down on gas at this point you should hear air spraying in TB, and then N20...  That means N2O is being delivered, now just find some open stretch of road and floor it and see what happens.  Monitor Air/Fuel ration very closely, if it gets under 0.89 volts shut it off and try bigger fuel jet.  Also a very important thing to have with N2O system is AutoLite 103 spark plugs gapped at 0.45 (or less, I have mine at .42) otherwise you will have a lot of hesitation, misfires and your car will feel like shit when running N2O.
Updates / Comments	August 27, 2001 After having this kit on my car for a while I finally got it to work fine.  I had a lot of fuel pressure problems (if you have aftermarket fuel pressure regulator adjust it with car on and WOT not by removing vacuum lines and other adjustment methods) but now everything works fine...  I also had to buy new aftermarket plug wires, stock wires were gone...  I also added pressure gauge to monitor pressure of bottle which should be over 800psi for best performance, and bottle heater to keep it above 800psi...  New personal best of 12.883@106.1 was achieved with 75hp shot (keep in mind that was without heads, headers and cam)... February 04, 2001 I got lots of emails from people asking how exactly do those vacuum lines connect to fuel pressure regulator and ZEX Box...  so I m including a picture that will hopefully answer your question... I believe that covers it, for any more information don't hesitate to email me at gtppower@hotmail.com Osman