[Gear Ration For Tt-01]

So which gear ratio makes the car go faster. I am currently running a 61/19 gear setup giving me a gear ratio of 3.21:1. Would a 55/25 give me more top end speed.

[Problem With Tt01-e]

I have recently started RC racing on carpet with the above standard kit. I have gradually upgraded the bearings, driveshaft and motor with no problems but I have just replaced the standard tamiya slick tyres (no inserts)with RP24's with foam inserts but I am now having problems cornering. Everything was OK with the tamiya tyres. The car is flipping/rolling over on each corner. Someone said the tyres are too grippy others have said the suspension is too hard or too soft.

Any advice would be appreciated.