if you are serious about diving there, you better be ready for some tremendous differences. First, I am guessing that you have never been in water colder than 80 degrees (just like me!). Heck, in Tioman, we freeze whenever it goes below 82. I am betting a 7mm suit AND hood and THICK gloves will let you get mostly submerged before you want to get back on the boat.
Also, and I could be wrong on this, but don't expect 10-20 meter viz with zillions of colorful reef fish and lots of hard and soft coral. Prepare yourself for "Hantu-like" viz, sand, rocks, a lot of kelp / sea grass and some silver and grey fish. It could be better than that but at least you'll go with low expectations.