I use Rapid for components. They do have a kind of drill down to find things but its not got anything like that site you linked me to. I did a quick search but i cant seem to find any transistors that rapid sell. Maybe im looking for the wrong things though. Now i can find the formulas i need and put the results into that page and hopefully find what i need and hopefully i wont end up using NPN transistors again where i need PNPs