Still wrestling with the issue on my 5.4 SR. The flooding hull does make a difference especially if you put on too much throttle initially - prop will just cavitate and you won't go anywhere. So you will accelerate better with a dry hull.
The other problem I've found is that the transom sits quite low in the water with the hull flooded and you're at rest. (This will depend on balance of boat, which could be better on mine and weight of engine) Obviously you can't drain it out of the trunks and you need a pump on the deck to keep it dry. Not a serious problem, just a bit of a pain and it can be a bit alarming in s chop!
As Paul suggests, you can go for a temporary fix to try it out but be warned, you will probably get plenty of water in the hull. Once it's in there you're stuck with it until you recover. That defintely doesn't help performance (yep - been there!)
My current thought is to block up all the holes as well as possible. I'll then put a bilge pump in the hull itself and pump out through one of the deck bung holes (assume the 4m has those?). Any pump maintenance means taking the transom bung out again, but hopefully won't be required too often.