Hi, the R1's gearbox is an integral part of the engine so has to be kept. I havent got reverse gear but its almost like a shopping trolley - easy to push with the roll bar. Where the chain sproket would go to drive the rear axle on the bike this is replaced. For rear engined cars you could keep this chain setup but as ive rotated the engine for front mounting the chain sproket is replaced with a sproket adapter to fix a propshaft. The propshafts are then custom made to accomodate a centre bearing so that the engine does not have to sit inline with the diff. The prop is usually a TRT with sliding joints to dampen the harsh running of the engine. reverse can be fitted for electrically with a starter motor and sprocket on the rear drive or a reverse box can be fitted. Both add some weight, expensive at £700+, steal power and are known to blow up. Diff and rear drive all remain pretty standard other than IRS setup, although at one point il probably upgrade to an LSD if needed after its been on track.