Bigger Intercoolers are cool! (pun).
The con with intercoolers is they need to have a size appropriate to the flow dynamics of the air passing through them.
the what? I hear you say.
Well, basically the larger surface area of the bigger intercooler allows for greater heat exchange (keeps intake air cooler for longer than stock) but, there is a point at which the longer and wider pipes will cause unhelpfull turbulence. This is most obvious at low or no boost level but can extend right through the power band if poorly matched.
It's like shooting a .22 bullet through a .44 barrel, the air rattles around and loses flow speed.
A lot of design can go into producing just the right size for your engine combo and driving style.
This bigger intercooler will not give you anything over the stock intercooler's power peak until you are pushing more than 350HP or so of air through it.
However it will lose less power than the stock unit if you drive on full boost for longer than 60 seconds or so. I don't know many people with large intercoolers who do this, so the rest have wasted the money for the time being. Most owners give short bursts of power over a quater mile where the run is less than 20 seconds.
anyway, go dyno your car now before you fit it and then after you fit it do it again, without changing anything but the intercooler. A bag of carrots says you are on the same power or less. (Note; don't do the run at the same place you buy things, the operators can fiddle the dyno to make it look good).
Last bit of advise; go buy yourself a light flywheel for $450 ,you will pick up far more power than you did for the intercooler and half the other things you have bought.