if you're dead set on the GSXR, then i'd say go for the 750. little bit more lower end power than a 600 which will get you moving a bit faster from a stop. you'll still have the handling of a 600 though. hell, anything made in the past few years handles as good as a 600. the only difference between bikes anymore is the power.
i thought Suzuki was going to stop making the 750 because it really doesn't have a place in the racing world anymore.
oh, i'd love to get my hands on your TL, provided it's a TLR not a TLS. probably the best jap twin on the market and it can hold it's own against ducs and aprillias.