I have at the minute a radtec front mount intercooler and was wondering if it is too big for the turbo to spool up efficiently due to the compressed air having to fill up a bigger space. I might be way off here but thought I'd get peoples views / experiences.

 

I'd have to agree with you. It will increase the turbo lag time due to the extra space needing to be filled as you said. Once its full though it can only help to get you cooler air.