What will it cost ya if you throw their bike into a ball of fire (not saying it will happen, but...)? If nothing, do it. If they charge you for a ruined bike, get your own. Would suck having to pay for a bike you don't own.
Just called and got the low down - $450 for the rental of the bike and all gear (sans helmet - although you can add it at additional cost) plus $100 non refundable deductible. I you go down its $350 that's it. Not too bad. Worst case scenario I spend $900...best case $550 and no worries of wadding my bike and can test the waters.
I'll play devil's advocate. According to my research, you can buy an SV650 for $3,300, race it for two years, then sell it for $3,400 on the WERA Classifieds. If you do get bit by the track bug, you'll find that your GSXR rarely gets ridden.
I still think you buy yourself a trackbike. Even renting a bike you're dumping a lot of money that could be put towards a trackbike instead. Also, make sure you have good health insurance and a way to get home in case you smash yourself up and can't drive.
your location alone says "sell street bike." CT? too much snow. '08 gixxers aren't going anywhere. sell it and get new girl while you're at it