I would have to agree that 18s look very well on our Contiques but I don't understand the logic behind
Anyways you will feel like your car is slower but thats just cause it takes more to turn them, you wont lose horsepower though
Correct me if I am wrong but doesn't it take (use) more power to turn more weight?!? Someone else here might have posted this but I will repeat it anyway... for every additional pound the engine has to turn (i.e. axles, WHEELS, etc...) you lose 2.7 hp. Unless you find a bad ass set of 18s that are super light (and let me know if you do!) you will lose hp, sorry. I don't mean to start trouble just stating facts.
Oh yea and I believe 19s are as large as our vehicles will fit

( and correct me if I am wrong)