There is one thing to note here.

The fact that it is more token efficient will itself lead it to be smarter since the context will be smaller for the same task. However, in opus models, you'll have built internal correlations like "if it did X it will usually do Y" which may not be true here, since grok 4.5 may have done X purely due to the smaller context size, but can't do Y cos it wasn't RLd on that pattern enough. So it will be a unique experience as far as opus tier models go.