I've just fitted a four way switch to my American Ash Telecaster. What a cool mod this is. For those who don't know, the extra position gives you series wiring when using both pickups. I was going to fit a humbucker at the neck but decided to go this way because I really like the front pickup as it is. The result is a tele with all the sounds it had before plus a faux-humbucker tone in position 4. Highly recommended with the caveat that it does depend on the pickups. The AA has Alnico 3s wound to about 7.1K and 7.3K on my meter and the series position would easily pass for a PAF type down at The Dog and Duck on a Saturday night :