I drive a 2003 F150 single cab truck, it only has 95k miles and it is an awesome truck. I spend about $350/month on gas. I'm trying to justifiy if I should keep it or not, I get about 12-15mpg on it, my commute to work is 40 miles all together. I'm looking for a good used luxury 4 door vehicle, such as an Audi A4. I'm 6'3, and I drove a 2012 Cadillac ATS, which was an amazing car, just I don't want my backseat passengers to feel cramped up when sitting behind me. So maybe an A6 would be a better idea. What would you recommend?