The 6mm Remington is a better design than the 243! Sharper shoulder and longer neck means less throat damage. Also it can be loaded faster than the 243 or the same speed with less pressure.
But since you already have it as a 243, is it worth the trouble to rechamber? Only you can make that decision.
As far as AI versions, I don't think they are worth messing with, other than improving that dreadful sloping shoulder of the 243.
I suspect that if you are limiting your hunting to Tennessee, you probably don't need a more powerful cartridge than the 243 though.
BTW:I currently own 2 6mm's and one 243. I've been shooting 6mm's since the early 60's -- getting over 55 years now.
