It definitely does have an impact on FPS. We see a drop off about 5fps. It is however in my mind the best scenery I bought. The use of photos, dynamic buildings is quite something. I did an arrival with the working title cj4 and it is simply incredible.
The amount of detail at the airport and the city is unparalleled. Run and get it if your system can handle it. I have an i9900k/2080ti and my son uses an i9700/2060 and we can both run it fine.