Can a Linksys WRT150N's antennas come off and be replaced with a better 7dBi and is 1.8 dBi to 7/10 dBi a huge deal? the better antenna im looking at can be seen here- HERE
They sell antena boosters as well as different size antennas but for your answer to your question no it wont make much of a difference. If the antanna does not screw off it is not made too be removed.