Getting an SF Line 3, having a non-authorized tech do major mods, then possibly finding out that you still don't like the sound is a pretty good recipe for ending up with a unit that no one else will buy from you without taking a major loss on your investment.
Your Line 3 would be virtually worthless to anyone else looking to get one. Not many people would consider buying a unit that's been heavily modified by an unknown tech, no matter how good you think his shop is.
Be patient and just wait for a fully upgraded Line 3 to come up for sale. They seem to every 3 months or so. Then, you can check it out and not lose money if it is not to your liking.
Otherwise, just get something else