I have the BDX 10.4 on my '05 M7. I like it, think it helps out. BDX is at bd-xtreme.com. Does need a different belt. Will need to do a little bit of modification to the angled structural bracket between the footrest and the bulkhead. Supposedly at full shift out the sheaves on the 10.4 can hit that. I haven't done anything with the belly pan but yes it will rub a little more. There is a little tub/protector on the newer sleds ('07 and up) that you can buy and modify your pan so you can install it. Provides a little more room at the bottom. I bought one two years ago but still haven't taken the time to install it. Haven't seen enough damage to warrant spending the time. But I'm not a hard rider. You might also check with Michelle (Freeagent on this forum) on her pricing for a Cat 10.4. She is typically very competive pricewise and her service is flat out second to none. Hope this helps some.
VDO