I talked with Bill Coore and Dave Axland about Kapalua a couple weeks ago. As Greg mentions, most of the details are in my article at GolfObserver.com.
There was an agriculture quarantine in effect when the Plantation course was originally seeded that outlawed importing certain grass types to Hawaii. This greatly limited what was available to Coore and Crenshaw. As a result, the Plantation course's greens were covered with TifDwarf Bermuda.
The greens are now covered with a new and improved Bermuda grass called TifEagle, that's apparently less coarse and grainy than the TifDwarf.
Coore very, very subtly recontoured a few greens while the grass was off, to create a few new hole locations - a new one on the right side of the eighth green, as requested by the PGA Tour, comes to mind. But, Coore says the recontouring is so subtle, very few people will notice any changes were made.
I was surprised to learn how much the green surfaces at the Plantation course had shrunken in over just 14 years. Coore says a few areas had crept in by as much as 10 feet! So, the re-grassing also allowed for quite a bit of green surface area, and in turn, some interesting hole locations on the outer edges of the greens, to be recaptured.
Bunkers throughout the course were reworked by Axland, Jeff Bradley and Tom Beck, too. And two new fairway bunkers - one each at the 15th and 16th holes - were installed.