Seriously...I had to read a couple post about 9 times before I understood wtf was being said...something about a truck kicking your ass 6 times and plugs being good for your car is all I got...oh and 80mph somewhere in there too...

Here is the deal. Get some damned Autolite 605's and be done PLEASE. Gap them at .050, get a PCM, put in the 180* T-Stat as it will make your car run cooler and last longer. Which is great since it sounds like you beat the living crap out of it. The Non-HD Tranny that is in your car is WEAK. If your gonna beat the crap out of it then go get a Trannyman95 transmission from Triple Edge Performance. Get a built 4T65 with 3.29's so you NEVER break anything since I doubt that car will see low-mid 12's.

List of crap. Follow this, as it all depends on how far you are going to take your car.

1) Fix your CAI/HAI/FWI like you said you were going to do.
2) Install the 180* T-Stat
3) Get a set of Autolite 605's/Stock AC Delco plugs gapped .050" (Use a gaping tool from a local auto parts store for $.99 or have them do it for you if you don't know how to do it)
4) Get a Downpipe. 2.5", as a 3" would be OVERKILL for a GT
5) Do PEM's (Ported Exhaust Manifolds)
6) Get a catback if you want...if not go to #7
7) Install a PCM (DHP, Overkill, HP Tuned/Powertuned, etc.)

Now here is where you have reached the point of the basic mods for a GT. You can either quit modding here or continue as now it gets a bit MORE pricey.

8) Ported TB, or HV3 Upper Insert (or Both)
9) Gen IV Aluminum Upper Intake (Get rid of that plastic crap, plus if you ever turbo it, it'll handle boost pressure A LOT better)
10) HD Differential from a GTP
11) If you are not going to Turbo or Supercharge/Twincharge the car then you will want to do a cam or rockers. Good luck on tuning a Twincharged car though if you do that.
12) Here is the step you can take now. Either do a cam OR rockers. You can't do both b/c the valve lift is too high. Go with 1.84 Roller Rockers for a easy 20HP. To get a bit more out of it you can get 1.9 RR, but you have to get upgraded valve springs (such as yellow #105's from a LS6/7 V8-and they only run like 20-40 bucks on ebay). Rockers do run about $350-$450 depending on what you get. Cam is cheaper, but you need a bunch of crap to install it and the COST of installing it as well, but you will make more power with a cam. For those you will still need to run the #105's (Some don't but I would never run stock springs with a high lift cam, as I am afraid of bustin' some chit). ZZ Performance sells a cam install kit and multiple cam choices for the GT. I have the XP in my GTP and love it. REALLY rough right now at start up since it is cold but once she gets running it goes like a raped ape. If I remember right they sell either the GT1 or GT2 cam, but I am not too sure.

Now from here on PLEASE read this before you go asking questions. AND hit the damned F7 button to spellcheck yourself.

And for the racing. But it in the Kills section, not here as people are only asking performance related issues, not dealing with whatever Dodge Ram or Chevy 1500 with a 4.3 Vortec V6 or H.O. 3.5 V6 you mighta' wiped the floor with.

And for the plugs, YES, take out the NGK TR55, they are too cold a plug for hardly any mods. Put in either the Autolite 605's or stock AC Delco ones. You car will thank you.

And thank you everyone for reading my rant...and if someone could either edit it or put their input in the mod list and maybe make this s STICKY for N/A 3800 owners...if there isn't already one.

*sigh* Now I am gonna go ice my fingers as they HURT LIKE A MOFO FOR TYPING THIS IN ABOUT 3 MINUTES