Just installed my second TJIAB with 14 lb mainspring into a M9A3. The stock trigger improved from 9/4 lbs to 8/3.2 lbs. Reset was also significantly shortened - probably a 30-50% reduction. Install this time only took about 30 min.
I put another on order for my 92A1 that is still at Wilson for some frame work. I decided to use the TJIAB rather than have Wilson perform the action tune...that should tell you how good this product is.