Hey there!! Try this for infinite knowledge! It will help you on a lot of the exhausts out there

http://www.turbomagazine.com/tech/0212tur_exhaust/

It doesn't have all of the exhausts out there but it does help. There are others like Stromung that are not on this list but offer similar gains and the fact that they offer a Dual Tip means that you get to look stealth while you blow others away. It is quieter then the ones that you listed though.

Let me know if I can do anything else for you!!

Thanks,
Brian

Flash N Dash Performance

 

Dunno about helix, but apexi gt spec is slightly louder than the hks. Both of them sound pretty much the same. IMO, the gt spec looks better because of it's slightly smaller tip and canister design. (I have the hks hi power exhaust).

 

i have the hks, it's not that loud, but on freeway it drones, tends to get annoying but then i have audio to save myself =]

 

Aren't there 2 HKS exhausts? the high power and the carbon ti?

 

yup. the carbon ti is lighter and more expensive

i have a apex gtspec. its perfect in every way

 

Borla single Tip! Full 3 inches, no extra flanges, deepest rumble. A tad bit quiter than the HKS. And it isn't super huge, so cops won't give you much of a look...

 

I would go for HKS, for two reasons: It looks great! Sounds Great! ok maybe three reasons, It produced the biggest gains for power in the test by turbo mag.

 

Lighter? How? It's the same exhaust....

plus the canister is just wrapped in carbon fiber, not made from carbon fiber...

 

i would get the hks hiper you save $200 on not getting the carbon wrap that you can spend on a BOV or uppipe. And if you scrape those bolt on speed bumps you wont rip your exhaust. I have been shown the way...

 

I'd go for the HKS Hi-Power in SS, since it still makes excellent power and costs less than its gaudy twin the Hi-Power Carbon Ti. Like TurnWRX said, it's the same as the SS but it has a titanium tip and C/F-wrapped canister. Not worth an extra $200 IMHO.
Also you may want to consider the Blitz Nur-Spec if you don't mind loudness. It makes excellent power as well, and looks pretty good IMHO.

 

i would go with HKS cuz the design and its not that loud like blitz, it makes most hp.