I would raise the engagemnet rpm some. The pipe, Most of the time...Will push you peak power band up alittle amd the low end can get alittle "boggy" so bumping it up helps get the rpms clsoer to where the pipe will work better. If you are that light then I wouldn't gear down either. On mine I had a Comet primary so I can't help much with spring colors on the stock set up....But their again, call Aaen. they can get you set up. From what I have seen with Aaen's usally are not the highest horse power pipe out thier, But have much better midrange then say benders or psi....and have a smoother pwoerband as well. Some of the other pipes make noticibly more "peak" power, But the Aaen's make better midrange...AKA, trail riding.