Instead of rebuilding, I would search around the internet for a remanufactured transmission. I am sure they can beat $1800.
When he gets the trans, if he has the time tell him to send out his valve body to IPT (
www.importperformancetrans.com) so they can install a shift kit for him. He will love the new feeling his car gives him every time it shifts. The shift kit is also a great product for extending the life of your transmission.
Also, when the shop fills the trans with fluid, be sure they check the fluid level in neutral. I cannot emphasize this enough.