Re: CR80 with shift kit
Bikeberry's shift kit was prone to breaking the front freewheel from what I hear.
But the avaerage shift kit costs $250 and up for the good SBP kit. Maybe add the HD front freewheel from SBP to improve reliability. I've had several problems with bikeberry and never had any good results. I will no longer buy from them, but your deal sounds pretty darn good on the numbers alone.
If more is better, then too much is just enough.
If you can't afford it, build it yourself.