I am about buy a car with a tekin rs and the guy took the soldering posts off and soldered the wires straight to the board. Is this a normal thing to do or should i stay away. He assured me (with great trader rating) that the esc works perfect.

dont buy it the post are the heat sink,you can and send it in to have new one put on but it will cost you

No that's not a normal thing to do. It will work but it lost the ability to shed heat since the posts act as a heat sink.

Offer less money.

There was a local guy at our track that did that and had no issues. He ran mod buggy with it (7.5 turn or so).