you cant compare the RG to the VG man lol the 9853 seem to work
me and a few others made the same mistake, this has a different crank, piston, sleeve and crankcase.
RG is a nice mill, but IMO i have seen the RG in a buggy rappin it out, and the VG installed in my Truggy is out performing that RG. here are some Dyno sheets that were posted by Tom wolf on the unlimited engineering thread, these dyno sheets were done by Ed at EB mods. he actually modded a VG just playing around, his mod comes awfully close to the Vspec according to the dyno, except it seems to be smoother in the mid.
unfortunately he didnt get to dyno the VG coupled to the JP-2, but by looking how well it performed on a mid sized track, it was awesome! cheap pipe in comparison to the OS 2060 2050 or the 086. which is why i personally would run the JP-2.
the other pipe you mentioned was also tested on the Dyno, so you can see for yourself which is best.