Universal bonnet distances. Raising the rear part of the bonnet significantly improves cooling of the engine compartment, which is very important, especially when the standard aspirated engine is equipped with a turbo. 2.5 cm. Fits all cars with M6x1.0 bonnet bolts. Universal bonnet distances. Raising the rear part of the bonnet improves cooling of the engine compartment. this is sometimes necessary when there is a problem with closing the bonnet after the swap.