If you can swing it, you should get the S/C. Up until 2010, the power difference is huge. The HSE will feel like your '04, but the S/C is pretty much... FAST. Aside from that, the S/C has a tighter suspension and definately handles better. The interior is a little more luxurious, the grills and taillights are different (personal taste) and the S/C comes with better brakes and 20" wheels. There were some minor interior changes around '07-'08, but I don't remember exactly what they were. Maybe the other members can be more specific on that . I would say drive both and shop around, there are alot of good choices in the market right now.