If you actually want to know you need pre/post iat and boost readings. Typically you want a core that is as thick and tall ass possible and keep length to a minimum. Longer only equates to more boost loss and doesnt really change iat anymore as most of the cooling is done in the first first 6inchs or so.
My pops runs the older BD unit and it showed about a 150* drop at wot. I have a htt cooler in my truck and the turbo side end tank has been welded 3 times. Blowed all 3 times at 60 to 65psi.