If you'll do a seach on here, you'll find several review threads from happy F.I. customers.
You won't find many reviews on HKS as the price doesn't justify the comparable gains to several other systems for 1/3 the cost.
If you are looking for an F.I. exhaust setup, they also make HFC's as well if you wanted to look into that option. However I have personally heard the Berk HFC/F.I. CBE setup and think it is AWESOME.
If you're looking for the exhaust to be loud and proud, but not obtrusive on daily driving, and plan to get the Berk HFC's, I'd recommend going with the 18" resonated, Stainless Steel Muffler F.I. CBE setup. It will keep down the volume while cruising, but wake up when you get on the throttle. The perfect combination of performance, sound, and cost effectiveness.
Also,
fellow PA member!