I have not got to play on the other turbos so I cant answer all the ???
hp= have not seen a single dyno test on any of the brands??
throttle response= I have an after market clutch kit (indy dans) 5-pounds boost 0-6000ft and on dense snow its a arm jerker and will stand vertical before the rear idler wheels meets where the ski was! {so yea way better than stock}
ease of install= silber has got to be the easiest and quickest {drill 1 hole in a rubber boot and put a T in an oil line the rest is plug and play}
trouble free= I have hade not one problem and has ran flawless from day 1!
first hand experiences= all
and hold on for the ride!!!
cost=if I remember right silber was the best priced{I bought mine off season when they hade a sail}