Top Hop-Ups
These items will make your car better...mostly lighter and more responsive, which is ever so important in the stock class:
-Upgrade to a full "Factory Team TC3." In your case it would probably be cheaper to by the kit and start new!
-Acer Ceramic Ball Bearings
-IRS Aluminum Imput shafts
-IRS composite Dogbones
-Stay with the Associated C/F drive shaft
Depending on the track, moving the batteries closer to the drive shaft can help greatly. Not really sure if blueprinting the diff cases truely helps you on the track but it does help the "WOW" factor at the track. Do a search for these in the forum.