Ronal,
I bought my Freak from Brent in Dec. I can not see how you could get a better quailty setup, although I have never seen the British version, I can tell you from personal experience the directions and fit of the box was perfect.
The only thing I had doubts about was the jets he sent with the kit 160's which seemed to big to me. I used Pat's carb. cal. and settled on 150's which Brent exchanged the 160's for.
I finally got out yesterday by myself with a couple of buddies and if was not for that new windshield and the buffeting over 75 I would have easily done 100+ when I opened it up on a straight away. I had to shut it down around 95 as I my head was bouch around like a ping ball.
Believe me Big Poppy was fast last year (as fast as I needed it to be) but after the freak there is comparison.
Go with Brent.
PS: The use of a bike jack will make the whole process painless and you will not destory the old box as most guys have to when removing it with out the a jack.