Hi Paul,
Trex is correct, I bought a Mosso 29er off eBay the other week with this kit fitted and although i have only done 75 miles on it so far, i can assure you that it will easily do 25 mph on the flat, i hit 36 (strava& Endomondo) on a slight downhill slope without even trying . On Saturday i did 10 miles along the canal and found it excellent, only needed L1 assist and the power delivery was nice and smooth. As for climbing on my return home from the canal i tried it up one of the hills, a nice 0.5 mile sharp climb. I used max assist but no throttle (would have gone way faster) and not really tying ( max heart rate 141) i knocked 17 seconds off the strava record ,average speed 23.9 mph. I definitely don't think you will be disappointed if it's speed your after.