To make a long story short after a couple years of riding, I bought a 2011 GSXR 600. I'm contemplating getting off the street all together and I think I may only do track. The only way to find that out is to go try it out. My question is though, would it be better to sell the 6 and buy a 250 to get some track experience or is it not worth the hassle and I should just run what I have? Sell the newer bike to buy an older already track prepped 6 or am I better of starting with a fresh bike? Thoughts and opinions would be great.
I agree with what has already been said. There is no right/wrong, just preference. Few years ago I bought a prepped 02 GSXR600, and am now building a 2010 GSXR750 I hope to race in AM Superbike in the future. Even an old(er) SS will get you to the front of expert category with enough skill development, so don't worry about the age of the bike at this point in your rider development.
That said, swapping down to a 250 may only be a short-term decision and you could end up looking for another bike within a year or two. So, selling your 2011, buying/selling a 250, then buying another sounds to me like a lot of stick hockey. Taking advantage of the track schools that offer the smaller displacement bikes could be all you need (BTW, FAST also offers 250's.)
All parts wear out, so there could also be a few unexpected costs with replacing parts, etc., that is only a result of when in their lifespan you happened to come into ownership of the bike. Also consider that with any purchase you should get the suspension refreshed and set-up properly, possibly also a valve clearance check if the seller does not know when it was done last. So these things should be considered on top of whatever you end up paying for a dedicated track bike.
I'm probably gonna get flamed for this, but your development as a rider may actually be fastest on your current bike. You already know it (and its maintenance history), and those gixxers can even be raced pretty much stock. You won't need to upgrade anything until it wears out first, then you can decide if you want to stay with stock or go for more specialized parts. At the very least I'd suggest getting a set of track bodywork and case covers to start out. Change the rest as you feel you need to (e.g., clip-ons, 520 chain conversion, rearsets)
So as long as you are not trying to make a podium contender, keeping your current ride may be somewhat more expensive but it could also give you less headaches. Just something to consider...
Good luck with whatever you choose!
John.