I had the cp-e on my first or 3 Fiesta ST's (back in 2016)
drove it for about 500 miles then removed it for the Mountune.
The cp-e is a great mount and we all know you prefer cp-e and Mountune parts. That's actually fine but it's a stiff mount regardless of preference. I've spoken to the owner of cp-e about making a street friendly or stage 1 mount as their Fiesta RMM is considered stage 2 which means "stiff" basically.
I've posted something like this before. It's merely my opinion and experience that the "firmness" scale is in the order below from most firm causing NVH off idle and or with AC on to least harsh, least amount of NVH. Don't get hung up on durometer numbers for each mount as some manufacturers have a different amount of leeway on their ratings and some are rubber (cp-e & Torque Solution) vs. Poly. Additionally, the different diameters of the large end and small end have an impact on NVH as well. We've used all the mounts listed below in our 2016, 2017, or 2018 Fiesta ST's.
1.) AWR 95a
2.) AWR 88a / revo
3.) AWR 70a / cp-e / Vudu / whoosh race
4.) Torque Solution / Mountune / whoosh street
5.) COBB