Intercooler advice please

Hi all, advice required please, I have an exMOD 90 which I have put a 200tdi into after the na was found to be toooo slow, can I make a bracket of sorts to fit an intercooler behind the existing rad or shall I just change for a 200tdi rad? Engine has a separate oil cooler, if I go for new is it just a bolt in job or do I have to modify anything?
Many thanks colin