worthwhile upgrade??

[dodgydiy]

i run a t1fk05 at club and it goes well. the only real downside on the track is the amount the balance of the car changes with the grip level. we run indoors on very low grip tarmac which changes a lot from week to week, one week the car will work, the next it is hard work to get it round. does anyone know if something like a t2 008 would be more balanced and consistent and a worthwhile upgrade?? or is there another car that may work well. i have spent a lot of time making the fk handle and can not seem to get rid of this trait. when grip is very low i sometimes drop back to an old tc3 which although it is slower, just works and is always driveable, just wish the xray would do this