I've owned a 2006 S40 for a few months now an would like to put a new exhaust system on my bike. When I do this I want to be able to fix the backfire issue with the bike as well. I'm super busy, so I'm going to have my mechanic do the installation and modifications. So, first off, what exhaust would you recommend? I don't want the bike to be annoyingly loud, just have a nice rumble to it. Accordingly, what size jets should I get (probably depends on the exhaust i choose, but please recommend) and should I completely remove the spacer?

Also, my front brake seems really weak. I've read on other forums that most of the braking is done in the front, but they must be talking about sport bikes. My rear brake locks up pretty easily, so it's hard to find a happy medium. What do you guys recommend? A drilled front rotor? More experience on my part?

I really appreaciate any advice

Awesome, thanks for your help  8)