The only problem with the 3.3 parts is the extra width which limits your wheel and tyre choice to revo offset.
With std offset maxx rims on 3.3 knuckles it puts the track width at nearly 14" which i think is a bit wide unless it's a very extended wheelbase.the wheelbase should always be greater than the track width i reckon or atleast close.
the hardcoreracing adress is this now BTW
http://hcrracing.com