Originally Posted by
Storm88000 Set your timing @ 19. Get a used CARB approved JWT pop charger. Look for some used JWT S4 cams. They go for like $350 usually. There are cheaper brands though, like Tomei, you can used for $200 but they don't make as much power. I wouldn't mess with the header because of the EGR and 02 sensor(s) if you are worried about smog stuff.
Just about every single SR had a EGR system and a O2 sensor. What this means is every single aftermarket header comes with provisions for both systems. What this means is an aftermarket header will pass emissions.visual/smog just as any stock header...............
Back on topic:
1) DEs respond VERY well (both N/A and epecially turbo) to JWT S4s cam and they are worth their weight in gold. JWT specifically developed the S4s with the DE in mind, so hence why they yield more power than the competition over a broader powerband and more consistent
2) 2.5" SS headers are also another good bang for the buck to free up some flow
3) A proper 2.5" exhaust with provisions for a CAT and a generously size reonator (keeps the decibles low) with a stock appearing muffler will also wake it up a little as well as get you past emissions/smog/visual
4) The difference between a CAI and a WAI are negligible, so whatever floats your boat. If you run a fender CAI, make sure it is sealed away from the elements (read: watch out for water)
5) Upping timing to 17degrees. But be aware: Upping the timing requires a minimum of 91 octane (but HIGHLY recommended you run 93 or higher). So although it garners power, over the long run, it WILL cost you money in gas.
6) A simple JWT ECU with a reflash should top it all off and make good on all your bolt ons.
Those means are fairly simple as you can find all those parts (sans the ecu as the NA setup is few and far between) here on the forum second hand which also keeps a majority of the costs in check
Good luck!