I've read that the 255 is overkill on NA engines but it seems that they are easier to find at around $70-80 while the 190 is harder to find at that price. Is it's okay to just go with the 255 although I won't really be using it to it's potential? or just get the 190? Who has the best prices? thanks guys.

 

Get the 190. The 255 flows too much for the stock regulator to be able to handle at stock fuel pressure. This will cause the engine to run rich. Unless you also want to upgrade the regulator, go with the 190.