Tip to manual gearbox swap? 964

[Dan911]

Hi,
I have found a 964, just sitting in someone's drive. It looks like car has not been driven (or cleaned) for many a year.

Track toy I think..

But it's a C2 - Tip! The car looks like it needs a full repaint (the paintwork has all gone white)

My question is - As I would want to turn into a track toy (strip out, cage, coilovers.... You get the picture) how much would it be to swap the gearbox out for a manual?

Thanks..