HMF pipes are well known, they perform well, are pretty cheap, they don't break, and are cool looking.

 

What kind of gain will i get with a slip on, aa pro flow (foam) and no airbox lid? Is 10-15% too much to ask?

 

I don't know about the raptor 350, but I'd say aroun 5-7HP

 

5-7 HP is about 25% of its HP, you'd be real lucky to get that... I bet you'll get 2-5HP, 7 seems way to high. But you probably get real good gains

 

HMF is the way to go....

 

Well, I'll tell you what! I ride a 660and opened the airbox with a K&N, I had a hell of a time jetting it because the hmf is so free flowing. I found the match at 180/185 with the needles on 5. It made a huge difference from stock, I cant keep the front wheels on the ground! I'm really happy with my HMF.

 

anyone know the Db of the HMF sport series without the quiet core?

 

What about without the quiet core?

 

I have an HMF without the quiet core and it is very loud. The decibel level, I couldn't tell you, but it can get a little obnoxious towards the end of a ride. To be honest with you, I'd say it has given me a couple of headaches. I usually ride in the back of the pack and no one ever has to turn around to see if I've fell behind. I have the blue colored canister and it looks really nice.

 

nepics?? i'd realyl like to get one... one of the blue ones...