I seriously doubt SBCL "destroys" Luajit. Or maybe it depends on the type of code. I remember a few years ago doing some Project Euler problems in both Common Lisp and Lua, and my recollection is that for that sort of code (nested loops, array accesses, fixnum arithmetic), SBCL ran code that had no type annotations significantly slower than Luajit, and with full type annotations SBCL only slightly faster than Luajit (and Lua uses no type annotations!). Of course, that type of code is probably in the JIT's sweet spot.

(I recognize this is unscientific and anecdotal, but I'm just trying to point out that it would take significant evidence to convince me SBCL is faster than Luajit, because my experience is the opposite.)