Is this a tuning problem???

[GotN2O]

Tuning experts needed here. I have an 01 SS Camaro, mods are as listed.
SLP Lid, Smooth bellow, SLP volant, Shaner S3 TB, descreened MAF, NGK TR-6 plugs and MSD wires, K & N filter, SLP coated LT headers, SLP y-pipe no cats, 02 sims, Magnaflow catback, TCI SSF 3500 stall, shift kit and tranny cooler, Texas Speed Magic Stick cam, subframe connectors, lower control arms and relocation brackets.
Texas speed dyno-tuned the car after cam install and it put down 373 RWHP and 370 torque. The tuner said I should easily see around low to mid 12s. He also told me a week previous they had a car similar to mine put down 385rwhp and ran consistent 12.2s there in Lubbock, TX. I ran my car in Roswell, NM a couple weeks later. Granted Roswell is a little higher up around 5000 feet. I figured I should see around 12.5s. The best the car would run was high 12.8s to 13 flat. Pretty dissapointing. The car seems to run very rich and will not idle correctly till it completely warms up. The gas mileage is around 12mpg. When cruising the car say around 35 to 40mph it surges really bad.
My question now after the long story is is this a tuning problem or what???
Any help is greatly appreciated, and sorry for the long post I just wanted to give all the details. Oh and the times were with Mickey Thompson ET streets.

[mrr23]

sounds like they need to do some cold start tuning. and some drivability tuning as well. ask if they did any of that or just did WOT tuning. there's more to tuning than just WOT.