Boat currently has thru hull with standard rubber hose to just transom pipe with flappers on the end. Keep that or switch over to tips with internal flappers?

Go with the tips! I have 4 4" SS tips coming out the back of my 233 and it looks bad ass!

I've got flappers at the moment and thinking of replacing as one flap finally ripped off. I like this boat but I wish I had my 233LS back, minus the OMC/stringer that was on it!

what happened to the formula?

The OMC stringer is a HUGE hole in the transom, it wasn't worth the money to replace it. I figured my current set up was in better shape, less headaches, etc. Also the shift cable got weird in the old OMC drive. Will tips be a lot louder than my flappers?