I'm considering a re-map on my '01 WRX, so far I have changed the filter and backbox (TSL group N), but do not really want to change the rest of the system, (or maybe just the 3rd cat keeping res center section).
Appreciate that more will be gained with full de-cat exhaust, but has anyone had a re-map without? what sort of results can be expected?

 

The '01/02 PPP is a backbox change, central cat removal and crude ECu tweak, the 03/04 PPP is the same with an Ecutek re-map, which should give you some idea . . . .