You need to get a commuter is what you need to do. I don't get how all of a sudden it's "too expensive" only 14k miles into ownership. Sounds to me like you bought the wrong car... good luck.
Curious, what's the prescribed drain interval in your manual?
All highway, and the interval is 10K miles.
In that case I don't see why M1 EP/AP wouldn't do the trick. It's still not gonna be an ultra cheap oil change but it'll certainly be cheaper than using Amsoil SS, Amsoil filter with UOA's every 3 months