I heard about the pups he uses in his sig model Strat; are they available on their own, and if not, what would be a good alternative that is relatively close to those?

When I tried an Eric Johnson strat it seems like they were underwound, other than that they weren't all that special. I should note though, pups aren't going to make you sound like eric johnson. If you want to sound like him I would check out his amp. Also, mod your strat so you can use the bridge + neck.
I don't give a shit if you listen to me or not
I know; I plan on getting a half-decent tube amp soon, and a pup change. I heard something about wiring an HS-2 somehow to get an EJ tone.

How would one go about modding a Strat to be able to use the bridge and neck? Could I have it done for me?