You have a lot of performance $$ into the car, what's your balance of "economy driving" vs. "performance driving"? Are options like a taller final drive on the table?
Try another grill block material - coroplast or plexiglass.
How about a kill switch so you can coast more often?
Power steering delete (pull the pump, drain the rack, cap the lines, get a shorter belt). Though this may be easier for me to say with a 1.8L engine over the front wheels than your 4.6L
