Have you checked to see how much clearance you actually have between the top of the shroud and the decklid?
10"x24" would make for a Big intercooler for these engines!
One cool thing looking at
www.paceproducts.co.uk would be to do a charge cooler which could be a little smaller than the air-to-air intercooler but packaging it may be a little more difficult.
We could do something like the CB Performance Carrera oil cooler set-up which used two small coolers up front to cool the oil. Instead, we could duct part of the air from the nostril vents (look at the duct run in your wheel well) from the duct before it takes the kink upward to a pair of small radiators/automotive heater cores or something that would cool the coolant that circulates through the chargecooler.
Or mount the radiator for the coolant underneath the vehicle if we could get good airflow (maybe with a fan for slow moving in traffic triggered by a coolant temp switch ), though using a front mounted system with copper tubing would disipate more heat I'd imagine.
What do you think?
I used to source parts like this for a company I used to work for that retrofit chargecoolers to early model Lotus Esprit Turbos.
That job sucked