I just got a 99 GTP as a daily driver as well. Had it about 2 weeks or so. DEFINITELY better/fast/bigger/more comfy/etc. than the totalled Grand Am GT it replaced.
Anyway, when I bought it mine had a DHP PCM, 3.4" pulley, cold air box, 12" brake upgrade and Buick Regal strut tower bars. I feel pretty confident in saying that this car, with that little work is a high 13/low 14 second car. When I do the exhaust work I know it will be atleast a high 13 second car. The DHP needs the exhaust upgrade to reach it's full potential. My next objective with the car is suspension and wheels so the car can handle the power it has.
Definitely a fun, easy car to drive and love. Good luck with yours and congratulations....oh and I agree, it ain't beatin' my GN!