I have an I/O in my Proline. I debated long and hard when I bought it because they also had an outboard right next to it. The box does take up some space but so to did the splash well for the outboard. Mine is a 1997 with a Chevy Vortec engine with a Volvo Penta outdrive. I have not had any problems with the engine at all. I change the oil myself every 50 hours. The only 2 things I find to be a slight bother 1. takes a while to winterize compared to an outboard. 2. Gotta remove the outdrive to check/lube the gimble bearing every other year. My mechanic always reminds me that if the engine ever goes, much cheaper to replace than an outboard.
