Looking for info on different options for belts. Tired of buying new $100 dollar belts every 200 miles or less, Has any body tested gates xtreme or marshall MTP belts on summits? I have had no luck with the 197 doo belt or the XS-803. I see the XS-821 is a cross for the 377 does that hold up? Currently running a 166 that I got last year with great results, but as we know they are no longer available. 2008 Summit 600 SDI 144". Stock except for clutch side panel opened up for cooling(frog skinz) and plastic belt guard removed. Clutch alignment has been checked. Thanks for any info.