I have an 07 M1000 with the RK TEK porting, head and clutch kit. It has been very reliable. I have been running it since 08, I have said this before, it doesn't feel like it has 225 HP maybe due to the slow revving of the 1000 but it is crazy the things it will do. I run all SW exhaust, and agree I don't really like the can, I switch back and forth from the factory to the SW can, I finally got a map on my boondocker I like that is way leaner than anything you will find on the manufactures website and it now works AWESOME with the SW can.
The only thing I don't like and it is not RK-Tek's fault is I can't get it to pull like a tractor. I have ridden T-Cats since 93 and miss that tractor grunt out of the hole.
I have basically spent the last two winters perfecting my boondocker setup and just haven't got the clutches dialed in yet. Was it worth the money-Yes, Would I buy from them again-Yes.