I have a few questions regarding the order of what I plan to do. First of all, I've already searched and found no definite answers to my specifics. So please spare me the flaming. Thanks.

I've recently bought an STi axle-back and nothing else.

1. Once I install this, would it be possible to go back later and replace my stock uppipe and/or downpipe?

2. Would I still need to replace my midpipe?

3. I was planning on an exhaust that's all from an STi, I just don't know if it's worth it. From what I've read, the uppipe is decent because it's catless. Is this true?

4. Lastly, once I finish my exhaust parts, would I need to buy an ECU or an Accessport to run with the exhaust system? Is it really necessary? Or can I just have an exhaust system and have considerable hp gains without an ECU reflash?

Thanks in advance for everyone's help. I've just recently decided to do some mods and probably will void my warranty. That leads me to my next and final question.

5. If I just install an STi axle-back, would it void my warranty? I really don't want to call my dealer yet to ask.


Once again, thanks.

 

I've recently bought an STi axle-back and nothing else.

1. Once I install this, would it be possible to go back later and replace my stock
uppipe and/or downpipe?

you mean with aftermarket parts? yes.

2. Would I still need to replace my midpipe?

no. the sti piece bolts onto the stock midpipe.

3. I was planning on an exhaust that's all from an STi, I just don't know if it's worth it. From what I've read, the uppipe is decent because it's catless. Is this true?

All aftermarket uppipes are catless, the STi is the only OEM catless uppipe. Yes it is nice because it is OEM but can be VERY! over priced. Almost all uppipes are the same, so brand isn't really an issue, just don't buy an ebay crap noname pipe.
-also a turbo back exhaust from an sti really isn't going to be that great. its still restrictive, however it's cheap. it all depends on what you want.

4. Lastly, once I finish my exhaust parts, would I need to buy an ECU or an Accessport to run with the exhaust system? Is it really necessary? Or can I just have an exhaust system and have considerable hp gains without an ECU reflash?

you can run an exhaust system just fine on the stock ecu. considerable gains??? depends on what you plan to do, if you go 3'' catless, you'll probably get 20whp. if you go with the sti turboback, maybe 10-15whp. side-note, you can get a catless turbo-xs stealthback for around $550 and bolt that STi axle back onto it just fine

Thanks in advance for everyone's help. I've just recently decided to do some mods and probably will void my warranty. That leads me to my next and final question.

5. If I just install an STi axle-back, would it void my warranty? I really don't want to call my dealer yet to ask.

an axle back should not give you any warrentee problems. of course it all depends on your service department.

 

wow thanks!

If I go with a 3" downpipe, wouldn't the 2.5" midpipe restrict it?

 

Most 3" downpipes that fit on the stock catback taper down to 2.5" to fit the 2.25" catback piping. It's not a big deal in regard to restriction but I suppose a 2.5" or 3" all the way through design like APS or Stromung would be better.

 

thanks again dude.... on with the modding!

 

Yup full 3'' would be perfect. I think the HP #s someone gave are a little high though. maybe crank hp but not wheel.