As far as I know, GP3 2k tracks has the same features as 1.13, but 2k's limits are higher... That's why you see some tracks which aren't compatible with 1.13 (like Belini's...)
GPGSL-3: Fox race driver and team manager - 2011-2012 Constructor Champion - 2012 Driver Champion
Season 9 - #18 Erick Von Draxeler - #35 Marcus Bongardt
And there are several other important differences. 18 circuits (I think) 7 gears, extra car art (prompted my Macca's named cars. Downside is the tools are not quite so slick (no GP3-2000Edit) different magic data. Hard choice bvut you can install both and take turns.