Fed Ex brought the wheel fairing this a.m. Not an overnight job. Instructions are 15 pages and involves removing the main wheels among other things. Last page lists the weight at 9.3 lbs.
The fiberglass (and other parts) look really good, should not require a lot of fussing to fit together well.
My weight was 741 pounds with all of the other options installed. That also includes a lot of priming of internal structure and interior paint. This will bring me over 750 pounds.
The effect of the pants on airspeed has been discussed here. See post #34 especially.
I feel sure the engineering is designed to maximize the performance within the rules.