I put the Power Core 4 on my bike, went and ordered the quiet insert the next day.
I work in a 90+db industry, I already have hearing trouble, the insert made it perfect, in traffic, pull the clutch a little blip, they hear me. I'm riding through Hollywood, traffic is hell, the straight Power Core was great, If i wanted to wear ear plugs.
I just put the DynoJet 2182 stage two kit, and removed the snorkel from the air box.
It's like the bike lost a hundred pounds, acceleration, the amount of throttle, it takes to keep 80mph.
I'll be back with a mileage report.
BTW Power Core 4 Muffler. too Loud.

 

A better horn does the trick too...

 

the horn on the klx is useless on the freeway...i can barely hear it...i'm embarrassed to use the horn in san francisco because it sounds like a scooter horn..haha...i use my throttle..

 

Go bigger

NAPA AUTO PARTS

Stronger than what I have on my Jeep.

 

for $15, i think i will! ...my 'turd is just sitting for 2 weeks now...waiting for a new gas tank...old gas tank was tampered with by an unknown and can't put any fuel in it....

 

I wired up the Stebel Nautlis on my KLX, sounds like a fire engine compared to the stock "meep meep".

 

I'm not talking about freeway riding.
I'm talking about, surface streets, in Hollywood, at 9:00am, okay, any time of day.
I have an almost Thirty Mile commute, in my car, it takes between, 1:30 and 1:50, on Sunday it takes forty minutes, there are days that it takes twenty minutes, on the freeway, and then, the last Four Miles, take half an hour.
On my bike it takes me 45 minutes, lane splitting on the gridlocked surface streets, is where the loud pipe comes in handy.