In theory, causing quicker spooling of the turbo by aliviating the backpressure, would cause the turbo to wear faster, is that correct?

 

4" piping is usually found much easier and cheaper than 3.5".

Reason being is that 3.5" isn't a normal size anything really uses, where as 4" is used often on diesels.

You can lighten it up by using 4" aluminum pipes from the downpipe back.

But it's all a waste IMO, for the extra money and noise, it's really not worth it.

I would say get a QUALITY 3" exhaust, with v-bands, and if you're looking for a little extra power, just drop the exhaust at the track/dyno. Maybe even weld up a little turn down with a vband so you don't get exhaust soot all over the underside of your car.

Bottom line, it's not necessary, and you certainly won't feel the 10hp you'll gain on your 600whp setup.