You may have hit your visual limit, but I bet there's lots of invisible mods you can make that can help you out.
You're already committed to the air dam. That's good, that will do a lot - you may have to do some A-B-A testing to ascertain how big is just right.
EM member
jedi_sol achieved good results on his WRX, generally agreed by many to be a crap choice for hypermiling, with
many subtle mods. He racked up tanks up to 32mpg, which is crazy good for a car rated for 20mpg combined.
I've seen it mentioned
elsewhere but also in my experience the cruise control actually hurts your fuel economy. In my Subaru it appears to affect how the transmission shifts, and in my Honda it's just not smart enough. You, with the added input from your Torque readout, can do more than the CC's stimulus-response paradigm can manage. I would guesstimate that the cruise control, while super convenient, sacrifices about 5-10%, at least in my case. YMMV.
This one depends on just how much of a gearhead/nerd you are, and your ambition: If you're willing to dig deep into your daily driver's engine programming, you could modify your ride to support Lean Burn Mode. This requires wideband O2 sensors, significant ECU modification (I'm not sure if it's a reflash or installing a whole custom ECU like a MegaSquirt module), probably some dyno time to get things zeroed in, and I have no idea what in the exhaust system. I have NO experience along these lines, only hours of fascinated reading from the likes of
pgfpro about his amazing race-on-Sunday-commute-on-Monday thrifty/quick
Mitsubishi Talon.
Just a couple of thoughts.