I was thinking of doing this myself, being I own an E-Maxx and Revo Roller. I am debating which one shall get the brushless and which one with titans.... muh hahahahaha
I initially set mine up with those, and I did have to change the gearing some what - but I dont recall which way. The Revo diff's have a different ratio than the Emaxx.
Losi 8T 1.0, Savage Flux - XL style, LST XXL, Muggy, 3.3 E-Revo Conversion and sitting outside 425hp, 831 Tq Dodge Ram Turbo Diesel. It SMOKES