I used mass loaded vinyl and adhesive to completely cover my floor boards and tunnel cover. It is available from mcmaster carr. It keeps the rattling down and does dampen some sound... some.

In regards to the pump. You can fill your new pump with atf fluid. When I had a horrid time starting one year at winter romp I learned this trick. I recently received a used 2.5 and we were able to start it on a pallet with a coffee can of diesel fuel. We did not prefill the pump even though it sat for 2 years. Just used the fuel pump on the engine to prime the pump, and then we cracked all 4 injector lines til they weeped. Started up nicely except for the acorns shooting out the manifold it was all good Best of luck.

Jason