Here is a good reason not to do this.

You will go, build a frame, realize that you want to build a better frame, realize that you don't have any of the tools to do so, buy the tools to do so, build a second frame, realize that the tools you bought were inferior and that your new frame is not as good a your first, build three more frames until you get a frame as good as the one you first made, buy new tools because you are tired of your ****ty ones even though now you have made them work.

$2000 first frame
$2000 first set of tools
$400 Second frame
$400 Third frame
$400 Fourth frame
$4000 second set of tools

$9200 two good frames, two bad frames, more tools then you know what to do with, and a $2000 car that needs a new engine.

Milo
Not to be pessimistic or anything.