yes and no, it will keep the engine running a bit cooler but sometimes the added weight of a larger radiator over comes its purpose. now your going to ask "how much weight will it add ?" and its just not the added weight of the radiator but the extra coolant cap. coolant is heavy, so having something that adds more coolant will also add more weight. so the trade-off is nill. now the 1 benifit is having an ALL aluminum radiator vs one wth plastic tanks which do leak.
Your engine should theoretically run right around the same temp as your t-stat.. give or take 20 degrees higher before the fans kick in. A 3 core aluminum radiator may cure some cooling problems (i.e. you live here in Tucson, run a/c full blast in traffic, have never flushed your coolant and have deposits.) All it will probably actually do is make your electric fan run less often when you're at speeds between 25-35 before the ram-air effect takes over.
If you don't have cooling issues, and you're just looking to ditch some weight, a regular aluminum would probably be fine, although the weight you'll loose won't be a whole heck of a lot.