I don't think you need to worry about it. I finally got around to having a proper ride on my 198b at a Sidcup practice trial last week. I recently finished a mostly cosmetic rebuild my brother started many years ago (prompted by me bending the gear shaft in a trial about 20 years ago) and the bike is bog stock and low mileage. I was even considering selling it but, having ridden it, changed my mind. I've not ridden a 350 so can only say that the 250 'plonks' along well, has good pick up, grips really well and revs out well - everything you want from a trials engine infact. I reckon you're going to love it!