I was a sales person of nst inc, no more now.
One of my dealer Expressatvs http://expressatvs.com handles a great service to it customers, the reason I knew that, because I supplied the parts to them.

 

I would keep the 250R.If you get rid of it you will probably regret it, most people seem to that I have talked with that have sold there's.I actually work with a guy that owns an 86 or 87 250R (can't remember the exact year that he told me) and as much as I bug him about selling his to me he won't, even though he hasn't ridden it in several years.

The 450 quads are fast and are fun to race.With a change to more aggresive tires, an aftermarket pipe, K&N filter, remove the airbox lid and re-jet the carb or re-program the ECU they become even more fun.If you can afford it I would buy a 450 quad and put it in your garage next to your 250R.You can always race both of them

 

The 250r probably the oldest bike around that you can still easily get all the parts for. i just recently stripped my bike and put it back together with all new connections for like 50 bucks.. i love my bike and its to the point now where the only quads beating it are the Drag Banshee's.. but i can still own them in a race. its a fun bike!