I'd beat you senseless using Standard Only Karts (The Rule my group uses to promote fair play and ONLY one of each standard can be used per each gameroom).
Anyways, best way to win is to learn how to "Cut Down" your Time. You can try racing me if you like as I've been practicing by myself to cut down times for every map without Snaking/PRB+Snaking (PRB=Start Boost, Snaking helps keep the boost if done consistently).
To shave time, you have to practice using the "Fastest Lanes/Lines" in each map (requires lots of trial and error) and a Kart that suits your style.
I prefer using ROB's Standard for general use (I was too good, so I used this to stop snaking and got pure speed) and Yoshi's Standard for Curvy Maps or when someone else is good.
Lastly, you need to play every map over and over again, regardless if you love or hate it, in order to get the best of each.
Anyways, hopefully you can beat my non-snake time on Rainbow Road - 2:10:388 (Mario+Rob Standard)