Got this from Turn One today.
I always had my pumps de-flowed and this seems to be a good off the shelf option from them for CMC 4th gens.

Pressure isn't an issue with the rack as long as its seals are in good condition and installed correctly. The flow rate however will need to be modified to work with the Mustang rack. If you are looking to get a new pump, you can order the LS1RX7 or LS1NIS*pump online and it would have the correct flow rate for the Mustang rack (which is 1.3gpm).