It's a little shy in the depth, but the length and width is spot on.
I have a precision 26.75"L x 6.20"H x 3.5"D intercooler and am making 350whp roughly, so at 7psi you will be covered. Although I would suggest going with a different brand....
You can get a generic intercooler man, and yeah that size is fine. I wouldn't pay out the ass for a piece of aluminum that does the same thing whether it has a brand stamp on it or not. The type of aluminum might make a difference as far as heat dissipation (if you want to get real technical and milk out every last whp at high boost), but for the most part the difference is not huge - ESPECIALLY not at 7 pounds.