Yes, using sealed classes, in addition to significant design benefits, can offer some performance benefits.
The design benefits (which you say you aren't interested in, but I'll include here for a complete answer) are that one can avoid the Brittle base class problem. Which, briefly, means a future change to a base class can cause problems if things aren't marked sealed.
As stated in the link you posted: "Sealing the virtual methods makes them candidates for inlining and other compiler optimizations" and "virtual members...are more expensive to call due to a virtual table lookup".
The .NET framework makes every attempt to optimize virtual dispatch, so by no means are virtual function calls 'expensive', but they are somewhat slower than a direct function call, or better yet an inlined function. This extra overhead is only significant if the function you are calling is extremely short (e.g. doesn't iterate over data), and if the function call is within a loop.
If you want detailed information on approximately how much slower a virtual function call is, consider this link.
As for the other keywords:
static functions are not overridable, so they are the same performance as sealed. All the rest will not make a difference in the performance of your class. However, as the link states, field and method design choices can (e.g. volatile fields are slower).