Congratualtions and good luck! Reselling speed parts is a very tough business to be in. I did it for a number of years and could never generate the volume of sales to actually make a living doing it. However, I did swing enough deals and sell enough stuff to keep me playing with cars during an extended unemplyment streak.
I feel there is greater margin to be made in the design and manufacture of the parts then the reselling. Items I could make usually had a 75-100% mark up whereas items I bought and resold were somewhere between 5-25%.
I also had the problem that I did not have a store front, but instead wanted to concentrate exclusively on internet and local swap meets. As such, ALL the distributors in my area refused to sell to me. I had to set up agreements with suppliers that were 500-1000 miles away from me, which also ate into profit margins as I had additional shipping charges I had to incur to build my inventory.
I also concentrate solely on Mopar parts, which became somewhat limiting. By adding other makes you could certainly expand your sales base, but it becomes a little differnt game when you can buy 6 dozen different types of small block chevy header bolts and you have a customer requsting the one set you chose not to stock.
But seriously, Best of luck. I still have a small inventory of mopar stuff left that I'd cut you a great deal on if your interested.
TC