Did you mean to type 30 x 30 or 300 x 300? Gas station would look more realistic on the smaller scale so if you're building to suite other needs, you may want to have the gas station look like a smaller attached section from the front...like you built the larger building onto an 'original' old station. Or have it as a separate unit if you had wanted it to look like an original country gas station store which some have done on this list.