nitro tc3 and RTR Nitro RS4 3 Evo questions
 

I jus purchased the hpi kit with the m3 body and have owned the tc3 for about 6 months. I was wondering which car you guys thought was better from every aspect. I havent got a chance to run the hpi yet, its got the .15 and 2 speed on the hpi, im real excited about this since my tc3 came with a one speed and .12. I purchased some spur and pinion gears made by team associated and kimbrough for my tc3, are these gears interchangeable with the hpi kit? also which kit is lighter?

No, I don't believe so. The TC3 is a lighter and overall a better car. The pitch are different between the two vehicles. You can try to make things work, but just keep the parts from their own manufacturer.