Racing Revo mods?

[SKiTZ]

I run a 3.3 with the Vantage chassis, pipe, wing, tank skid, Tekno box, wing mount, and servo mount, pull start, Proline 23mm hubs, 40 series velocity wheels, and bow ties. I need it to be faster. What would you suggest I do next? Lets start with the cheepest stuff first and work our way up. I say this because the truck is not mine. I work for Hobbytown and its the shop racing truck. They are very picky about how much they put into it.So let me know what you think? Thanks guys!