Wow really? That's almost an $8k bike and the shop seriously slammed the seat forward and now you're considering a short stem? Yikes

Did you buy the 56cm version when probably the 54 would've been better?

FWIW I've been working on my fit in my old LeMond, that has a top tube length a couple cm longer then it should. I swapped a 110mm stem that was level (-17°) for a flipped up 17° 90mm stem and it is noticably more "fast turning". I wanted a more upright position for longer days in the saddle. Also I replaced my setback post for a zero setback. The LeMond is a 55 ST x 56 TT so in the future I'll be looking at TTs that are 54CM.