Only real upgrade for a TC3 on oval that you might want is aluminum steering knuckles. Team CRC still makes/sells them on their website (http://www.teamcrc.com/crc/modules.p...od&prodID=3021
Not sure about the VCS3, but you should be able to use other shocks on a TC3. The only issue you might run into is shaft length. Most of the newer cars/shocks seem to be designed for cars with lower shock towers.
If you want more adjustments on camber links, you can use the TC4 chassis braces with the TC3 shock towers. If you upgrade to TC4 shock towers, you will need to use the TC4 chassis braces.
One other tip is to use the F+0 on the rear a-arm mount. This will give almost no rear toe-in, which will help the car rotate.
On oval, the TC3 should have a bit of an advantage since the batteries are on the left & they are further from the center line (compared to most modern touring cars). The extra battery slot is also a good place to put weight/ballast.