Trick flow heads how are they ?

Local shop priced me out some a week ago ... $1450.00 Canadian each plus tax and shipping... so around $3500.00...plus rockers. I figured that was a bit much for me to be the first local tester.
That same shop built a promaxx CNC headed small block 408 this winter that made 525hp with a small roller cam, air gap intake ...they are also about to do a another 408 with the CNC promaxx heads in the next few weeks...this one has lots of compression, a big solid roller and super Vic intake... shooting for 600hp
Thank you