Bigger intercoolers cause more lag when changing gears unless you can wot shift - if you have no lift shift it dosent matter but it can't be generated for our gearboxes, I switched a small 6 row intercooler for a 16 row and noticed the spool acted differently, looked meaner sticking out the bumper though that's the only difference, as ross said it takes more time to fill especially when your running a dv
I have a small universal one sitting here which whent in perfectly behind the vts bumper, I think you can get similar ones from toyosports or the alikes, no point going too big