Outer Limits 4x4 Board

I just bought a 2nd hand Subaru (Legacy?) water to air intercooler for $120!
I'm planning to fit it on my 80series which is supercharged. And I have a rather large amount of questions about it!

Sorry about the dodgy paintshop job but its the quickest way to explain what I'm after. The inlet/outlet that comes across the underneath of the intercooler has to be removed and a 2.5 inch outlet to be welded where i've painted the red block. Would this work or would the air flow not go where it's supposed to? Or worse would it hit the water/air core cutting in and welding there?
Also is it worth getting it pressure tested so I know there isn't any leaks in it? Or would shoving a hose into one of the water pipes be enough to see if it leaks? Thanks for any input people!

Also how much heat should I be trying to take out of the air? The air gets to about 110degrees C (just cruising around probably higher when I push it) post charger so should I be looking at about 50 degrees below that for an efficient system?

Cheers for any insight

i bought one of these but havnt gor around to fitting it yet, just putting the hose in wont pressurise the unit, i used a radiator pressure tester on mine and filled it with water, i could find no leaks on mine,

not sure about moving the outlet,