How soon are you looking to make the upgrade? I’m planning on the vmp 676 with 79mm pulley to get closer to 700 whp. Should have it done in a few weeks and can let you know.
I’m currently on the Phase 1 Roush as well.
If you can swing the Roush, then go for it. I have a 17 PP with the Stage 3 Roush and have not had any reliability issues with it this far. The MT is clunky at first until it gets warmed up. Good luck.
Long shot, but anybody in the Strongsville/Medina area able to run a diagnostic scan on my 17 mustang. My check engine code is on and curious to know what it is prior to taking it to the dealership. PM me if you are willing to swing by. Thanks!