you can install them.i had my installed by my local mechanic.had to have the carbs reset for airflow,also may need to step up a jet size.i would do it your self then take yor boat in and have them tune the carbs to the reeds.the hardest part is resetting the linkage etc for the carbs so they open at the right time.i seen better starts,faster holeshot,and about 3-5mph on the top end.the advantage to them is if you lose one they will not destroy the power head over your stock steel reed.are they worth the 130-150 bucks? sure if you are looking for a little performance.you may also want to talk to montyracing@montyracing.com. he has a lot of knowledge on johnson/evinrude motors and makeing them go fast.