Im buying a transponder and was wondering if i can buy a servo extention and run the wire out the reciever box so i can change the unit from one car to the other easily. Or will this not work since the transponder has two wire harness.

Yes that will work fine.

Thax just wanted to make sure that worked before i ordered it. I wonder if i should get a futaba plug or hi tech or it wont matter i have some of both tranponders and they both plug into my esc.

I made some 2 wire extensions and use deans mini plugs. Same concept and works great.

http://www.amainhobbies.com/product_...ized-Connector