I don't know how much they charge for a re-stall, so it would be best to call them directly. However, even if you are correct with the $350 price, it is still half the cost of a new converter. Don't forget that if you buy the new converter you will still be paying shipping one way.
restall: $350 + 100 (Max shipping) = $450
new converter $700 + 50(max shipping) = $750
It still looks like it is a savings of $300 to re-stall the old one.
All that said, you can probably sell the old 9/11 for $300 and then end up with a brand new converter in the car for the same price it would be to re-stall it.
I have heard good things about CK's 10.5, but have no first hand knowledge.