Yeh that's right for HP, not if you have a personal unsecured loan.
My gut tells me is a no no, its whether you feel brave enough to take the risk of the engine/gearbox going pop and them finding out you had modified it and hit you up with the bill as the lease is void.
Te other side is whether your company insurance covers modified cars, as that's another disaster waiting to happen if you were unfortunate enough to be involved in a serious accident.
All worst case scenarios and probably a bit ott, but you get the idea.
