When i put rims on my wife's car, I could feel a big difference in how the car drove. They were heavier than a stock steel rim and made the car seem heavier and accel slower. You are correct in your assumption abouot a lighter wheel being easier to spin, the car will feel more nimble because there is less rotational stress. One problem I see is if you want a chrome look, you will have a difficult time finding a lightweight chrome rim. If you want a lightweight rim, first of all you will need to pay alot of money, and secondly, go for racing brand rims. off the top of my head, BBS, Konig, Enkei, Rota, and even Dunlop make good rims but you will find that almost all of them are made of some type of aluminum alloy. Chrome to me is for show, which is fine, but will be heavier. as for tires, rubber compounds vary in weight but not to a noticable point. what you do want is a nice sports/racing tire if you want less drag. This is all from my own opinion, If im wrong with any of this, please correct me when all yall chime in.
JR