They sound incredible. The GFS Liverpool is exactly the sound I was wanting. Very very vintagey. Sounds great through my Ashdown Peacemaker 40 amp. Only $37.95. That's why I didn't want to pay $45.00 each to have them installed. I bought these pups at:
http://store.guitarfetish.com/vintagestyle.html Here's a sound clip of the Liverpool from their site.
http://www.guitarfetish.com/GFS_WAV/R12_Clean.mp3
For my neck I used GFS Lil Puncher which is a rail/blade tele neck pickup. I couldn't find a sound clip so I wasn't sure what to expect but I knew 2 other Squier '51 owners had used it and were happy with it. I love it.
Tomorrow I'll have pictures of my mod'ed Squier '51. The custom diamond plate pickguard is awesome.
The Martin was easy to fix. I used thin plywood just like you said and I glued it with some Liquid Nails glue. I only had to try once to get it right. Good thing I have small hands that fit in the soundhole. It looks so good that I didn't even use stickers on it.
I think mod'ing is gonna be an addiction.