I have just started my build. I am using an E30 donor. Everything seems pretty straightforward up until now with just one or two "issues" to sort out. Only time will tell if it goes smoothly thru' to the end.
The E30 is pretty simple mechanically with just the sloght complication of an engine ECU. Some otherv guys are using an E36 donor and things don't seem to quite so easy.
I guess about 10k is right for a build as long as you don't get silly with the extras. You are gonna be spending it over a period of at least a year so that makes it not feel quite so bad.
If you want a chat then send me a personal mail to email@example.com
and I will mail you back my phone number.
Got to go now - I need to order some nuts and bolts....