Prop question and noise reduction

[Thundergod]

So I have a 1997 sunsetter lx with the 320 monsoon motor

It is running a stainless 13x13 I would like to lower the RPM a little some prop help would be great

I went on the wake prop site and they where calling for a 13x12 which I would think would raise my rpm more

Boat runs well but is loud Overton doesn't seem to have an insulation kit anymore so a link would be great if any one knows of a place

[Bozboat]

Switching to a new Acme prop 515, or 525, or the OJ equivalent will be a noticeable improvement. If your spinning one of those oem SS props that throw blades, switching now could save you some big trouble.

[REW]

You can insulate your doghouse without a kit. used http://www.lowes.com/pd_13353-56291-ST16025_4294858104__?productId=1014123&Ns=p_product_qty_sales_dollar|1&pl=1&currentURL=%3FgoToProdList%3Dtrue%26Ns%3Dp_product_qty_sales_dollar%7C1&facetInfo= and some spray adhesive.

It wont stop the exhaust noise just the motor noise.