My current seat situation: drivers seat is okay but a bit dirty. I've tried to clean it with some specified seat-cleaning products but there is always some dirt in the grooves, which makes it look bad. Passenger seat is busted and needs new covers.

Is there any superduper product i can use to get rid of the dirt?

Get some TSP. Should be able to find it at a hardware store. TSP stands for Tri-Sodium Phosphate. That was the active ingredient that used to be used in laundry detergent, until the government banned it for polution reasons. I have used it for years on the white seats in my convertible. Works great. Just be sure to rinse it well after you clean with it.