Malossi Gear Kit 23/64 For Rally 200-P200-PX200-Stella
Malossi taller Gear Kit 23/64 for T5, Rally 200-P200E-PX200cc (and also Stella, but it's taller on the Stella)(does NOT fit Cosa style clutches).
These work really well for high speed driving and up-gears to about 8% taller.
Requires a full tear down to install, but it's worth the trouble. You should really have a cylinder kit to pull these taller gears.