Having owned an Apex Mtn. since 09 I've looked into a turbo for a long time. I've never even heard of a Rock and Roll turbo.
Personally for me I would buy an Impulse or McXpress turbo. They both have standalone EFI which adjusts the boost for me. Since I'm in the flats (1200-1400ft) I want something I can just put in the trailer and go west and ride the mountains and not be adjusting fuel settings all day like the Boondockers. Boondocker kits also had other issues with them. I believe they would blow a little oil out the breather and something with the exhaust on them. It's been awhile since I researched that.
But my choice hands down would be Impulse or McXpress. Boondocker turbod Apex's can be bought for cheap though if you aren't afraid to adjust your fuel for the temp/altitude/etc.
Lots of turbo info over on the 4 stroke side and at snowestonline.com I've spent hours researching this stuff. Just my opinion.