I have been around the Boondocker and Silber turbos for a few years- and both are very reliable- and consitant in performance IMHO..You wont go wrong with either-The Axys is a fun factor winner with a turbo.
Silber is the easiest to install- very straight forward.
But again, being a dealer for Silber - I tend to lean to easy install for the first time turbo clients-that want to get their hand dirty.
I do install for those that don't wanna even mess with it.
It's a great do-it yourself project that you will have fun with, a step by step video, and will be able to completely understand the install and the workings, with zero special tools required...
HALF the fun of adding mod's to a sled is being able to do it yourself, work through it, refine it they way YOU WANT IT, and above all, having that feeling of accomplishment!
Good luck on your choice- I have had ZERO concerns on the Silber Turbo's that are running out of my shop, or met and rode with that have them on their Axys.