I was simply trying to tell the original poster that I would not modify the D3. Using a filter would be far better even if it did take a long exposure. My advise is always to buy a less expensive D100 or D70 if he wants to have a camera modified. Guess I did not explain that well.Are you sure Gordon?
The internal filter on a D3 is at least a stop (probably quite a bit more, I haven't measured it carefully) less sensitive than an unmodified D70 when I tried it initially with a near-IR filter.
Can re-do the test if it's important to know, but for myself I'd not recommend an un-modified D3 for IR.