Year of manufacture: Subtract the first two digits of the serial number from 100. Example: Ser. No. 93XXXX = 2007 year of manufacture.
Lighten the trigger: The 900 series rifles already have the T-900 triggers; an improvement over the 800 and 700 series triggers. You can polish parts or replace the trigger spring with a ball point pen spring. Check out rimfirecentral for that.
Mags: CDNN, Midway, Cheaper Than Dirt. Bud's Gun Shop has them for the least but don't know what shipping will set you back. CDNN has free shipping on orders over $99 thru Monday at noon.