While it can be fun to debate the features of $100 tools, with NO insight as to the policies of the school the OP intends to attend, there is an elephant in the room.
@OP, contact the Engineering School as ask what their policies are on the use of calculators. Per course, per test, etc...
Don't throw money away buying the newest and best. When you get admitted in another year or so, you'll find out what the most current policy is. You may find out that you need to keep your TI-84 for homework only, and that you'll have to buy a more basic scientific calculator to use on class-work, quizzes, exams.
When I was admitted to UMO engineering school, NO calculators were allowed, and if students turned in homework or lab reports with levels of accuracy that were considered unachievable with a decent slide-rule, you would be invited to an interview at the dean's office. Back then a simple 4-function calculator cost as much as 1/2 a semester's tuition, and the college felt that it would be a serious handicap for poorer students. I left college and worked for a couple of years after my Junior year, and when I returned to take more courses, lo-and-behold, you were allowed to use calculators in class and on tests. Things change. Get the appropriate, approved tools and learn how to use them before you take your first class.