Depends on what you're going to use the car for.

Ground Control is a very popular coilover sleeve set-up, and koni yellows are likewise very popular. There are better systems out there but they'll cost much more than $800 (rough cost of the GC + koni setup above).

If you're just doing bolt-ons, several companies make a 4-2-1 header for the gsr. Comptech's piece is nice; pricey, but it's pretty good for bolt-on purposes. 2.25" collector does get restrictive later down the road...

Shingo