Frame rates are going to entirely depend on your hardware, sim, etc. The product is benchmarked by the developers against a vanilla X-Plane 11.50+ (no custom scenery, plugins, etc.) running Vulkan/Metal, and not in VR. If you read this forum you’ll see there are some VR limitations, such as with the FBO interaction. You may have to go in/out of VR to get the full product experience.
There is a beta being developed to provide preliminary support for X-Plane 12, however final support will not be committed to until 12 itself is out of early access beta.
The size of the plane isn’t really relevant, if you’re thinking because it’s a business jet it’ll be less complex than an airliner. In fact for some systems the Challenger is more complicated than an airliner.
As far as the simulation goes, I think it’s fair to say it’s the most sophisticated simulation available in any consumer-focused desktop simulator. However, it is also programmed with efficiency in mind, and makes heavy use of multithreading to not impact the sim’s frame rate as much as possible.
Just keep that in mind when comparing the recommended specifications on the product page with your own PC hardware.