I'm wanting to tinker on my XRR to gain a bit more fear factor . For a play bike, 50/50 street & trail riding, what engine performance mods (in order) are proven? It's uncorked but other wise stock engine & runs very well. I'd like a bit more mid, upper midrange without sacraficing too much grunt. I don't want it much if any louder than it is with the HRC tip. I'm running stock gearing & wish I had a lower first & a high fifth for cruising so I'll probrably leave the gearing alone. I was thinking about a cam swap, but didn't know if it would be benficial with the stock pipe? Is there really any measurable gain modifying the airbox lid on a milder motor?