I stocked up on pulleys recently and have these on hand ready to ship, 3 custom tunes are included. 93 Octane usually nets 620WHP
Link to order :
https://www.unleashedtuning.com/ford-gt-sct-x4-2-8-pulley-package/
It is generally best to remove the rear pan. There are a wide variety of dyno types, installations, and tie down pickup points that will vary location to location to consider. I just take mine off beforehand then you are good.