another option is the m2 wheel packs, those i will buy because of the style of wheels included. as we all know someone needs to come out with resonably priced wheels in a set. making 2 peice molds and using resin for the wheels are easy, however some of the tires will be a pain due and would require a 2 part mold as well... so honestly the best option is as i suggested. buy cheap cars for the wheels, and replace the wheels with the wheels you dont like and donate/give away the casting to neighborhood kids or make a junk yard. and sorry to say, alot of mattels castings now have plastic bases excepet for certian cars. yeah i like a diecast base but is it a necessity? not for me as its rarely seen. that and most of the cars i collect(japanese cars) very rarely have a diecast base unless its something like a GL or JL or what have you.