Ash is right about the 2pc. and generally where the weight savings are being had.

From a "feeling" perspective, i really didn't notice much from losing a couple pounds going to the 2pc, however, i did notice a slight change in mpg. It's minor and not a selling point for going lighter there.

The change to RP03s, was a little more noticeable. However, it was swapping for lighter tires that made the most noticeable difference.

On a similar note, i'm swapping out my BC coil springs with Swifts, which are allegedly lighter than the BCs while offering a much better ride (i.e. true linear, regardless of compression.) It's a custom-build but should have it before the year ends. I'll try to get a weight comparison and post back then.