As it appears that the most relevant advice has been provided, I'll toss in something else.
You will probably import from one location to another. Maybe even to another drive. When you set up the new drive, take care to organize it well. Unfortunately, Apple provides some pretty poor file system options that are not particularly optimized for massive storage requirements. So, it may be worth it to consider partitioning the drive into smaller chunks - by catalog or even by year. Or it may be a PITA. But it will make any search faster.