The 65 and the 80 use the same turbo
( 5435 970 0002 Borg warner K series ) If you want extra power just fit a set of 80 bhp injectors - its as simple as that !!
( 80BHP EJBR01801A as suppose to the 65BHP injectors EJBR01401Z )
A remap may help give a little extra power
You could fit an intercooler but it wouldnt really do much on such a low power engine.
We run a DCi65 bhp Clio courtesy car with the 80 bhp injectors and it goes like snot of a stick !!