HKS Hi Power Spec L at 3,4&5k Rpms
 

https://m.youtube.com/watch?feature=...&v=zcIW-5tXVns

Sound clip of HKS Spec L (BT001) hi power Catback with all other oem stock. Sound deep, and in my opinion only slightly louder than Invidea Q300. Substantially lighter than stock or Q300 at about 24 lbs. Slight but noticeable increase in acceleration; which I did not expect based on reading of this thread.


Apologies to admin in posting to separate thread, but was unable to figure out how to attach to compilation thread

Imho it misses important point. How loud are cold starts. As for acceleration (and braking, and cornering, and fuel economy) .. yes, even 24lbs off can enhance it .. but imho to be felt as more then placebo, some more weight cuts need to be made. With 100lbs or even more - i would beleave. With less .. for average person it's placeboo thing. Otherwise even driving with almost empty or full tank of gas would be noticeable for anybody. For thickheaded me .. i usually notice weight changes only if they are at least comparable to one passenger worth of weight.

Idle at start of video. In Texas so a truly cold start is rare. Maybe placebo effect on acceleration, but I think the effect is coming less constriction on back flow rather than weight.

I had the Spec-l for a while, sounded great until I added a header.

.. or less constriction. But which also adds not more then +5hp from catback without tune, probably less, also hard to felt with 'butt dyno' :). My bet is rather impression from sound, kind of contrary, when few did sound-tube delete mod & felt like if car had become slower :)
As for cold start .. dunno, i bought mine half a year ago in late & cold autumn, so hasn't yet seen how starts are in warm weather and if in warm weather ECU also pushes richer fuel / plays with ignition timing / higher idle rpms on engine startup, like it does in cold weather. While stock exhaust is still reasonably quiet for that, my collegue's WRX cold starts are hellish loud for first minute, and he really has to mind neighbourhood ears. In few vids of aftermarket exhausts i've seen similar issue, so imho it's important enough point to fully evaluate noise of some specific exhaust.

Here's my HKS Spec L with Tomei front pipe.

[ame="https://www.youtube.com/watch?v=8uwBfSHvc-w"]HKS Spec L + Tomei Type 60 Cold Start | Subaru BRZ - YouTube[/ame]

The Spec L alone wasn't doing it for me. It was alright under load and on deceleration, but wasn't substantially different than stock. I heard more engine noise than anything when revving. The quality and fit was very good, and it is very light for a duel exit. It looks great in my opinion too (lightweight version anyways). Paired with the front pipe (and now overpipe) it sounds really nice in my opinion, but with a header I think I will have to go to a catted or resonated FP or it will be too raspy.