Looks like I was right in my original post, there is justification for lecci bikes :-) Just come back to this post and glanced at some of the comments. Having fitted four conversions now I have a couple of thoughts that might be useful. Pale rider is right, in that none are what I would call 'powerful', but, then you probably fit them for 'assistance'. I found fitting front wheel kits worked well and actually helped handling, probably because you then have an 'all wheel drive effect'. Certainly better on corners, if surface is poor.
Re: torq arms - I would say an absolute must, especially on front kits on bikes without beefed up forks, learnt a lesson on Thorn Tours, when the drop outs appeared to 'spread'!!
Put larger, rear kits on full suss mountain bikes, and on these, rear is the way to go, mainly for traction.
As far as backup goes, there is no reason for this not being available. I've dealt with Cyclotricity throughout, and, they have been very good. They seem to have struggled with demand more recently, and hopefully service won't deteriorate!