As far as engineering schools go, UofI Urbana is one of the best, making it a very good school for architectual design too. When I applied to the mechanical engineering program in 06, I had a 4.0 GPA and a 29 on the ACT and wasn’t accepted. There are so many similar applicants, I’m a firm believer in luck of the draw. As far as a minimum GPA, my guess is a 3.0–3.5. Good luck, I love Champaign.