You shouldn't have paid this much big amount in first place, until and unless the deed is written on some official piece of paper so that the dealer is bound to deliver the car in time. If he fails to deliver the car in time with your mentioned working systems or he backs off for some other reason, you have got evidence to prove him wrong and recover your money.
But lets hope for the best InshaAllah there won't be any such thing as he might be arranging those system to get them install in the car that you finalized and for which you paid him the token money.
Regards