Dont be sold by pub talk figures though guys. Its only all too often someone gets a remap done and ends up with a huge bhp or ft-lb figure, and that could be down to any number of reasons including;
Type of rolling road
How the car was tied to/ran on the rolling road
Amount of boost being used on the map
Type of fuel used
etc
etc
However most importantly is the actual way the car delivers its power.
I have seen a graph for a BWJ engined car (Cupra/Ed30) on an otherwise standard car that spiked at 340ft-lbs then fell away progressively to approx 100ft-lbs less by the high end of the rev range.
Some tuners manage to maintain approx 300ft-lbs across the rev range on the same engine therefore has more "usable" torque all of the time instead of a kick up the ass, a massive amount of wheelspin then a big tail off.
However as far as pub talk is concerned, the car with 340ft-lb would be the one people said "wow" to.
Same thing is possble for power where the peak power is too high too early or the power plot may be all over the place, but the "number" associated with it happens to be high.
You have to choose your map based on your own preferences, but for many they would include;
Location/Availability
Price
Perceived opinion from others/press
Reputation and quality (ie do we know that the car is not running lean toward the top end of the revs)
Switchability and no flash counter increase
etc
Poll