l wanted to know what kind of affordable exhaust system is the best to get.

Leave it the way it is. If you modify it in any way Subaru will void the warranty.

Replacing the exhaust will not void ur warranty. The dealer may try to deny it but under federal law the manufacturer has to prove that a failure was caused by the modification. So if ur tranny goes the dealer may argue that ur new exhaust increased the HP sooooo much that it trashed the tranny, but if u threaten to sue them they will probably back off.

As to ur question, u will be much better served by finding WRX enthusiast websites & finding out what the older members recommend than asking .

There are many brands available such as Fujitsubo, HKS, Supersprint, Zerosports, Greddy etc. Happy searching!!

HKS, Greddy,

Here is a link to Gruppe-S. l got pretty much all my parts from them.

http://gruppe-s.com/Subaru/subex.htm

Here is a link to the North American Subaru Impreza Owners Club. You can ask WRX / ST l owners what they have.

http://nasioc.com/

And u might want to look into getting a reflash for ur WRX after u finished upgrading all ur bolt ons. Shiv at Vishnu Tuning is well known for his work on EVOs, STIs, & WRXs.

http://vishnutuning.com/wrx_stage0_v265.htm