Turbo XS DownPipe. Good or Bad?

[SuBeast]

I was just reading up on the Turbo XS DownPipe, and this one on EBAY is a massive 4". Is there like a limit to where the size doesn't help you anymore. Would this 4" DP be a lot better than the usual 3"DP? And this Turbo XS DP is bellmouthed. Its pretty pricy though. Idk if it would be worth it.
eBay Motors: TurboXS Subaru WRX / STi 4" Catless Downpipe WS-DP (item 120213331857 end time Jan-27-08 19:07:14 PST)

[TDub]

That depends on what your goals are. If you're just planning on upgrading to a 20g or something, 4" is not going to make any difference. Someone correct me if i'm wrong, but i think the 3" downpipes are plenty big enough for most daily-driver applications.

[Kjott21]

The TurboXS DP is good and not any pricier than any other name brand DP.

[Boostbuddy]

4 inch DP will hurt your HP and TQ unless you have a big turbo to fill it...a little bit of back pressure is good.

[SuBeast]

yeah thats what i was thinking. Because IF/WHEN i upgrade turbos, it still isn't going to be that big, i'll get either a 16g or an 18g. most likely the 16g...

[mosc]

Originally Posted by Boostbuddy

4 inch DP will hurt your HP and TQ unless you have a big turbo to fill it...a little bit of back pressure is good.

This is false. The turbo itself creates more than sufficient back pressure.