I don't think it will throw things that far off but I would get the A/F's looked at just to be extra safe.
well since its a Side Mount he has right now, the psi drop is not that much and say the motor was tuned for 10 psi.
considering all else equal, he gets a larger front mount, which the psi drom before and after will be more, but not by that much.
so he runnin 10 psi before, now it will be lower, unless his wg actuator vac line is on the other side of the intercooler.
therefore would not necissarily need a retune unless something more major was changed, such as manifold, exhaust, different charge pipes, engine internals. or trying to push boost up further than 10.
tru the larger intercooler will change flow as well and cfm but not too much.