Second the vote for the GTO.
Coupe. RWD. 350 horsepower and plenty of room for a 5'10" person and a useable back seat. And the LS1 is one of the best engines ever built and they don't crap out too easily and the gas mileage for the power is pretty good. The styling isn't the greatest but it's not going to be as outrageous and I think it would fit a female cop's personality.
And since the 05 GTOs are about to come out in a few months the 04s are going for dirt cheap because nobody wants to pay the full price for a car that's going to have 50 fewer horses than the newer versions. I've been talking to several folks that are getting them for around 25-26k.
Check out these websites and go hit up a Pontiac dealer
www.newagegto.com
www.ls1gto.com