I wouldn't worry too much about the fuel economy, I'd worry about the cost of maintenance.
I owned a Conquest TSI my senior year in college. That thing was a blast to drive and I'd still love to own one. BUT, that thing nickel and dimed me to death.
These were rather rare cars when in production, and there is no real aftermarket for parts.Look up brake parts (rotors) at autozone/advanced/napa. They don't even carry the 5 lug rotors. I purchased tires for mine and found that there are only a few tires made in the correct sizes, and they are NOT cheap.
If you are considering this car as a daily driver I would look for something else unless you want to spend every last dime you have keeping it on the road.