450 vs. 409 opinions needed - sound

[NautiqueJeff]

The dealer also told me that if you didn't use premium fuel in the 450 it would de-tune the HP according to what they believed from PCM.

This is true. It is in the manual.

[DealsGapCobra]

The OP says he has tested the 405. My suggestion would be to test it once more with a group of people and full ballast.

I will say that I have never heard anyone complain about having too much power, but then you asked about noise and I can't help with that. Why not contact CC?

[gride]

In Alabama an engine can't produce more than 85 db @ 50 minimum distance. The only boats that ever bother me are go fast boats doing 50 around corners.

[Miljack]

Is the 450 a dual exhaust, or limited restriction muffler? Must be a reason it's louder. I asked a sales guy how the 450 makes more power than the 409 and I got a "canned" reply about extra "technology" for the 450. I didn't slap him, but it was tempting!
If noise is a big consideration, the FAE would help a TON. We put one on our unmuffled big block Python, and it was a different boat.
From what I can see here, and from other sources, the 450 is the engine to have in the G23 (minimum). Just look at the listed weight+stock ballast, it's around 8,300 #'s!! That's a LOT of boat to be pulling up on plane...
Our 230 is listed @ 4200, and I had it loaded with stock + Flyhi (650 arrow+2 750's)+stock (900), and it took a while to get on plane with only 2 people on board, and one rider...That's 7205 # and with the ZR6 (390hp in our boat), it took a while to get it up on plane!
FWIW

[djmekinac]

The 450 is a single exhaust same as the 409, more revolutions, different cam and engine mapping (ECU) are responsible for the extra power.

Did not make a real difference in the sound heard from the dock compared to a ZR6 in my opinion. Also, when loaded like yours (Mijack 230),
even a 450 struggles out of the hole, there is too much weight in the back (around 2100 + engine and people against around 1000 in front).
Let me clarify the "struggle" affirmation, it takes longer to get on plane compare to stock ballast, which is really fast.

That being said I would definitely put at least the 450 in a G23 and my only choice would be between the 450 and the XS550.

Ultimately, the money would be the main consideration.