There aren't too many hills in the city. However I must agree that my car feels really slow when the engine is cold and the engine doesn't 'sing' as "well" as it does when it's warm either.
I use Mobil 1's Synthetic ATF in it.
The engine is still fairly strong too. Starts up great and runs amazing once it's warm. Then again my commute consists of really short run. When I went to Hammonasett the car was just awesome.
A LOT 
of power when I needed it and transmission was amazingly smooth, etc.