I'm building a OMP Edge 540 and ran out of balsa. Still have the ailerons to build, so i went to the LHS and bought some 1/4x1/4 and 1/4x3/8. The balsa is the standard "house of balsa brand" and it just does not appear to be the same grade that came with the kit. The density of the wood is not as dense as the wood that came with the kit. Should I find a better source to buy better quality balsa to finish the ailerons with or am I being paranoid. Just don't want to lose a plane because of poor quality balsa.

You might try the LHS for 1/4" sheet that has the density you are looking for and then, using a stripping tool, cut your own strips of 1/4sq and 1/4X3/8, most mail order places have a Min. order on balsa but I use Balsa USA and Lone Star with good luck.
Both will hand pick your choice or density and grain for a small fee.