Stock E-maxx Setup on E Revo?

[TexasSP]

I am thinking of building another E Revo for other people to drive when they are with me that just uses the stock Titans and EVX. For those of you who have done this, what was the top gearing you ran. Is it stuck pretty much at 18/66 like the e-maxx or can I go higher on the pinion, say 20t or 22t?

I have all these parts sitting there like the titans, EVX, axles, arms, and junk I thought this would be worth while.