Hi Jared, thanks for giving the post a read. I guess I am assuming too much in the exhaust section. Most of the Headers sold are either sold with a Cat delete pipe or with high flow cat pipe that replaces you current cat.
Power gains from just a hi flow cat are little or none based on my research so far. Cat back upgrades give decent gains and the header, hi flow combo gives good gains. The two together are your typical full exhaust upgrade.
Matt, yeah I wasnt confused neccesarily its that my frame of reference is, as you mentioned, '96 and up especially the '98 - '05 RS community and '97 -'05 L /OBS community. That seems to be were most of the questions come from. I am aware you can find older turbo motors for around $1000 but again as you mention there are some significant issues in using these motors for swap in the newer generation of Imps.
Andys, we are not beign sensitive per se, its just that everytime some one logs on to the N/A Forum for specific information on N/A tuning someone with a WRX or a turboed car has to chime in and make everyone feel stupid for even answering the OPs question. After awhile it gets plain irritating. If the poster is asking whats a better value for my $2000, a turbo or n/a tuning then it makes sense for those who have swapped to contribute.
However I can not tell you how many times a poster says in the first paragraph," how do a make good power from my 2.5L or 2.2L motor and I'm not interested in turbo" and not two replies later you get the obligatory " its a waste of money just do a swap, N/A power is a waste of money!"Oops... I'm not trying to beat up on you Andys, apparently Matt and I were posting simultaneously
The point of my original document was to provide comprehensive list of generally accepted tuning options that for the most part provide real power gains for ppl interested in N/A tuning. It was also to suggest that with some patience it can be done in a reasonable budget that makes it a viable alternative to doing the swap thing.
ON the throttle body spacer, my understanding to the benefits of the device is derived from the effective lengthing of the plenum portion of the intake manifold. I read several articles on the web but really didnt bookmark them so I can provide a reference right now. This technique is not new, it is one of the older muscle car tuning tricks that is still used effectively today by the lovers of the big block motors.
1320 used to have dynos on it and a thread on www.rs25.com
provides an extensive review, most of them quite favorable.