Big surprise.....went to my local store today to get some ideas for electronics in my 2010 D-40 BG.....I like D-TAR dual source in my F50-R and I've read good things about DiMarzio and LR Baggs.....the store only stocks Martin and LR Baggs pickups, so I thought I'd give the Baggs M1A sound hole pickup a try (no M80s in stock).....my buddy said he'd throw it in my D-40 and I could try it out through my Bose for a few days.....came back a couple minutes later and said my sound hole was too small....kind of surprised me, thought my D-40 would probably have a "standard" size sound hole, but I guess not.....I didn't write down any measurements, but my Guild sound hole was 1/4" smaller than the Martins.....it's my only guitar without electronics, so if anyone has any advice on my situation, I'm all ears! thanks, gang...