I wouldn't pull it, I'd put it in a window and find out what it is. I've never been able to make my brain imagine my plants, topped and LST'd even, growing for 12 weeks and still fitting in a computer case. I really hope you show us how they look in 2 1/2 months, still in the case. I do hope it works out, it just doesn't seem like enough space but I'm probably wrong.
My veg cabinet is all CFL's, while the flower tent is 400w hps. The cabinet has been running 77-111 while the tent has been 77-95, but I think that must be because the cabinet is so much smaller than the tent, and all the heat is trapped in there (like it will be in your computer case). Plus there are 5x 100w cfl's in that little area. So I can see how the guy thought CFL's were hotter, but overall cfl's are much cooler, and my temps are only due to their environment. Imagine all the heat from a 400w hps inside a computer case - that would be some crazy heat.
If heat becomes a problem, consider running your lights at night to reduce the heat. I've read electricity is also cheaper at night but I don't know for sure.