Personally, if the X fits your needs I wouldn't change. The cost of the transaction (taxes, fees, financing, whatever) will make this an expensive venture. This cash can be deployed else where.

I always find it funny that people complain about something like mpg (maybe not in this case) then go out and spend money trying to solve the problem, only to get into an unknown situation with new repair costs or buy a newer car and take the depreciation hits, but never factor those costs into the decision.

It is like when housing was skyrocketing but people never included interest, property taxes, housing repairs, etc into their 'investment' decision...

Keep the X, go lighter on the gas pedal.