I currently ride a 2003 Masi Speciale (steel frame, 105 groupset, shimano 540 wheelset). All parts are in fine working order, but I've gotten more serious with my riding the last couple of years and am looking to upgrade. Rather than buying an entirely new bike the plan is to replace items over time.

I am interested upgrading to 1) Lynskey's R230 frame, 2) SRAM Force groupset, and 3) Mavic Ksyrium sl wheelset (or something similar).

Ignoring opportunistic purchasing based on price, which upgrade will have the greatest impact on the quality of the overall ride? I am not a racer, and have no interest in ever racing. I am your average "weekend warrior" who rides ~ 150 miles per week and enjoys a few centuries every summer. (Other upgrades, e.g., seat, seat post, stem, headset, etc. will be done as needed.)

Thanks.