I'll take the opposite point of view here. I was a TA for Electrical Engineering students about 10 years ago while I was in graduate school. This is probably outdated advice, but whatever...
In a typical US 4-year engineering program you will do very little taxing computer work in your first 2 years. You'll have an introduction to engineering course to learn a little bit of each discipline, but the school may even have a computer lab to play with the programs. By the time you benefit from some processing power, your powerful laptop will be outdated, still heavy, have degraded battery life, and it might even be in need of hinge or fan repair. I wouldn't sweat the computing requirements set forth by the university too heavily. If I was spending my own money, I would get a cheap, light, and portable windows laptop for day 1, and an upgradable desktop computer when I needed it. Something with a full-size case and a modern processor.
Since you are spending someone else's money, see if they would cover two computers. If not, just get the nicest ultrabook you can find. 500GB SSD is enough. Maybe minimum 16GB of RAM and 8 hour battery? Processor and graphics capability are not as important.