Mario - I'm about to change my brakes too.  Did a lot of web reading - several threads on this subject at The Hull Truth.  Lot's of guys swearing by the Kodiak brakes Putershark pointed out (but spendy).  Several happy with Tie Downs - new ones are vented I guess to help cooling, but also some unhappy Tie Down Customers.  Believe our actuators will work if you puncture a diaphram (pressure release valve?) to keep light residual pressure typical with drums out of the way.  You need a reverse solenoid too.  After checking with the guru (aka Codfish, who put a pair of tie down discs on a prior single axle trailer and was happy with them) he pointed out that you can get a pair of replacement drums for the price of a single disc and not have to worry about actuator changes.  I just ordered new drums from Eastern Marine and will be installing soon.  I bought the boat/trailer used and they just had the 3rd season with lots of salt and minimal flushing before I got into the picture.  Quite a lot of rust, and some adjustment challenges so I figure it is time.....Barry