I installed a set of coated msds headers and y 2 weeks
ago and left the stock exhaust on till after holidays.
As far as sound it is hardly noticeable.Just a tad
throatier.The performance increased is the best part.
Even with the stock exhaust I noticed right away how
more responsive it is at low and mid range no metter how
much throttle and it doesn't die out after 6500 like it
used to.I'd say headers and y on their own are good for
10 hp and for sure the best bolt on I've done till now.