Hi Tonytodd,
Yours is a classic beginning prolem we've all had; so don't feel alone.
Here's a place to look. If the company you are interested in isn't on this list, it might be a problem; so increase the depth and intensity of your research.
If your ideal car manufacturer is on this list, you are off to a good start, in my opinion:
http://www.cobracountry.com/cobmfrs.html
The next choice for you to make is budget, followed by your driving style from trailer queen to hard core racer. Then you must decide whether or not you want to do most of the building, part of it, or none of it.
After your decision making/research, be sure you drive the car(s) you are interested in to determine its "fit" to your needs.
I believe that 20K is on the edge of too little wheres 50K will allow for some special bells and whistles.
Good luck on your "journey."
All the best,