As Begbie said, best to talk to Barbz
Effectively you are getting a whole new engine. Think he has a price for the basic conversion and then the sky is the limit on top depending what 'extras' you go for... Its the extras such as titanium rods / pistons and motec etc you need for massive power.
JohnS or Maveric may be willing to comment on their budgets, but to give you an idea of the cost of some extras alone:
Motec ECU + mapping 1k-3k
Custom Turbo 500-2k
Twin plate clutch 1k
Uprated Brakes 200-2k
Uprated rods + pistons 1k-3k
Those prices would apply to any coupe, not just a 2.4 and don't really take account of labour.