The Pypes and Hooker are pretty much identical sans the mufflers. I have had both. The Hookers did rust a little at a weld that I did. I do think the Pypes with Race Pros are VERY similar to the Hooker with Super Turbos which is what I had. The Race Pros are slightly louder, in a good way. You need to make sure the test pipe mates to the cat back system. Your options are:
1-Hooker-2 1/2" nice system, not stainless and HEAVY
2-Pypes-2 1/2" nice system, 409 stainless, lighter or
3-GN1/TR Custom System-3", light as a feather, 304 stainless, beautiful, but to me a little raspy
I believe the GN1/TR Custom System is modeled after the old ATR system. The old ATR system is nice but VERY rare. You can YouTube it and hear the Pypes, Hooker and GN1 (TR Custom) exhausts. You can also buy the Pypes system without the mufflers and then get the polished (chrome looking) RacePros. Both the Hooker and Pypes slightly drone but not a deal breaker.
And to make things more complicated there is a Flowmaster system (409 stainless I think) that sounds really nice (it was in a Flemings YouTube GN for sale video-the exhaust is at 6:01). Sounds like a V8. But I would never get Flowmasters for a turbo car. Plus the car in that video is under a roof, near a wall, and cold (higher RPM's) which makes the sound louder. As with all exhausts the cat, or lack of one, downpipe, heads, etc will all influence the sound.
I have a hybrid system, 3"downpipe, test pipe w/electric cutout, Hooker Y pipe, 304 polished Pypes RacePros and then GN1 3" tails all with band clamps. I absolutely love the sound and look. Looks bada$$ from the rear. You can check out Buick Grand National Drive in YouTube. It is pretty lame but you get the idea of the exhaust. It is louder than what you hear. I'll make a better one when I have time. HTH.