Thanks for the pointer - I had read about it, but hadn't put two and two together. The kinds of things I work on (cacheable wesbites) don't need to be highly tuned for back-end performance, so I guess it's easier for me to do that.
Lit style probably doesn't have much impact on performances, it's handled by the parser and mostly by ignoring the comments.
It can impact the memory of runtime-oriented languages, especially if they keep the text around (e.g. for reflection or whatever) but that's about it.