Hi Rudycob1,
The G46 kit is still available and is being sold by ribble kits. I purchased the moulds from Gary 18 months ago and made sure that all previous orders were fulfilled so there are a few still being built at the moment although I have been unable to keep as up to date as I would have liked due to my working abroad all year in places that don't have reliable lines of communication. Because of this I would suggest that the best person to contact would be AndyP57, who can often reply to any queries much quicker than I can, either by pm on here or at
andyp@ribble-kits.co.uk.
As for donor cars, SE5s have a lot going for them, easy to work on, V6 engine sounds great, cheap and plentiful parts etc. Another option that I considered was a TVR wedge although these are often more expensive to buy and would require the kit to be shortened to get the correct wheel base but a nice fast V8 version would be fantastic!