I am pretty new to the sport and I was wondering if I messed with the air intake would that put my car into a new class that I don't want it to be in. Specifically, I have a 98 z28, with Koni's and sway bars so it is running in FSP. I want to put a TSP lid on, but I don't want to go into prepared. Is this allowed? and how else can I enhance my car without crossing over into prepared? I'm assuming messing with the Cams etc. is out of the question. Thanks

 

It depends on what club you run with. Usually an air lid or any other mods will take you out of stock class. The only mods I know of that are stock legal in most clubs are front sway bars and (sometimes) shocks.

 

You could put on a blower and totally skip Prepared and hop straight into Race

I'd check the clubs rulebook if you're concerned about which class you'll be in. You might be able to use any 1LE equipment which was an option in your model year without penalty.

 

To give a reply from a different view - I run a 98 Z28 M6 in FS. I have every mod that I can think of that is permissible in FS. Some of these items are not exactly mods, but are (maybe) helpful in a very minor way:

Suspension/Handling:
Suspension Techniques 35mm Front Swaybar
Koni SA's up front (set to 7 or 8 out of 10 stiffness)
3rd Gen Bilstein HD's in the rear
Aggressive alignment (max. static negative camber/max. static positive camber/total toe out 1/16")
Kuhmo Victoracer V700s 245/45R16

5-pt. Harness to keep me planted in the seat

Brakes:
Hawk HP+ front
Hawk HPS rear (less aggressive pad to yield less rear brake)

Engine/Drivetrain:
K&N Airfilter
Amsoil 5w30 in the Engine
Red Line D4 Synthetic Fluid in the Tranny
NGK Iridium Spark Plugs
Magencore Spark Plug Wires
SLP Loudmouth Cat-back
Red Line 75W90NS Gear Oil (NS - no posi additive to assist in stronger posi action)

This car does not feel/sound "stock" when driving or riding in it. It handles great on the autocross course as well as the street. The only downside to this setup is on open track days - the front bar is too big and the stock rear bar is too small. If I enter a turn too hard on the road course, I find myself trailbraking to get more front grip. This is a small price to pay to have a decent autocross setup.

FS to ESP to CP is the traditional f-body progression, but you can also go to SM. Check the rulebook for what you can/can't do in those classes. The TSP lid would likely put you into ESP or possibly CP. It is possible (and arguable) that doing all of the engine "mods" above could get you around the same increase as the lid...

The real question that you need to ask yourself is how important autocross is to you. If you wanna test your skills and try to win your class, you need to max out your car for that class and go for it. If your primary goal is to have the mods you want and autocross for fun, then you will have to accept that your car won't be maxed out for class and will put you at a disadvantage that only better driving will overcome...

Last year, I decided that I wanted to win FS locally so I bought the car (sold my 88 IROC) and did those mods. Assuming that I win FS this year (likely), I am going to start modding my car to my own liking for road courses, not to fit an autocross class. ...likely going to CP... My $0.02

...and the only way that you can run 1LE parts is to run ALL 1LE parts. You can't cherry pick, so there will be a few non-performance items that you will have to add.