Well, the Langster is a good choice as a street machine. It's set up as a single speed (freewheel), not fixed gear, although I believe it can be converted to fixed. Stock gearing is 42 x 16, which is an easy 69 gear inches with 700 x 23c tires. It comes with 2 water bottle mounts, whereas the Kilo only has one or none. I agree that you should first use one of the GT rental bikes before buying a dedicated track bike, and I'd look for a used one for sale on the TXBRA forum classified when you decide to buy one.