i hadn't really looked at it that closely and I had thought that the castings would be similar enough to fudge it. but all things considered I have probably been relatively lucky to encounter no compatibility problems already. I agree with you about just buying a new kit tho- I can't afford to make this into a full function. It's that thing about dipping your toes in the water a bit at a time when you should just jump in. If you happen to know where I can get a pair (or 1) of those optional gears RRR( thank-you very kindly RRR) pictured (i immediately recognized the part - there is one in my spares) that would be interesting. Now I think I have to decide which one(or 2) to buy as a full function kit