So regarding the recent trigger weight and drop test conversations, I put my Lyman (I know, not the best) digital pull gauge on my three SPRs just now.
First Gen - 3lb,15.8oz average. I've never messed with this trigger. The rifle shoots great, so I've never messed with anything aside from skim bedding the action into the stock.
A1 - 2lb, 5.2oz average. That worried me because I've just read all these posts about that being potentially unsafe. So I cocked it again and dropped it six times onto the recoil pad from about a foot off of my concrete floor. No issues.
A2 - 2lb, 6.8oz average. Did the same drop test, and passed.
I took my A1 and A2 triggers apart a while ago and polished the crap out of the contact surfaces with Mother's mag and aluminum polish on the head of a q-tip. Took probably 30 minutes to do each. Then I backed the two nuts off close to as far as they'd go and that was it.
I checked both at the time for safety. My little routine is cycling the bolt 10 times, then cycling the safety 10 times, then smacking the reassembled rifle off my knee 10 times again. If it passes that, then I'm content. If it doesn't, then I correct the issue.
At this point I'm of the opinion you can get the SPR trigger a touch under 2.5lbs and still be safe...but I don't think you could get it down to 2.