If you are working on dynamics problems in NEiNastran with an eye toward acoustics, you may want to cosider VNoise.
It is a fully capable BEM code that has a direct interface to NEiNastran and FEMAP. It is a fraction of the cost of Sysnoise.
For a large scale model such as a ship, you may want to consider a package with craig bampton or similar substructuring method. MSC and NE Nastran offer this capability.
I would guess that since you have mentioned noise and vibration analysis and ProEngineer, you are attempting to analyse the response of a "virtual" model based on your solid model. It is possible to tranfer Pro geometry to virtually any pre processor or desktop FEA pakage.
Depending on the...
