hello, i am Thierry lefevre from holland, i have at the moment a ET 4 blade prop...but i wanne chance my prop to a mercury pro max prob............i try to get information everywhere even bij mercury belgium if if i now turn a 30P et prop , the mercury pro max 30 p wil be also good for my...wil my engine make the same rpm with it...? ore is ther a big difference.....it is onbeliveble that nobody of de dealer in begium knows the anser on that......HOW can i buy that prop than...? .......PLEASE HELP MY..!!!!!!