I have a 92 mustang lx notch and I have the 14 inch polly wheels and I bought a set of the 16 inch gt pony five spoke wheels and I was wondering what I have to do to put those on...I know they will just bolt right up but I would amagine that I will not read the correct miles per hour now...I think tha t I hurd from somewere that I am going to have to change the speedometer gear is that correct...and if that is true is that hard to do and were can I get one??? thanks