I let out the shoulder straps in the harness some.
I needed more lead.
I needed bigger fins for the rockboots.
That's about it for gear really.
Oh, I recommend a good DS class. You CAN learn on your own, but a class, (or solid mentor), can shorten the learning curve significantly. I thought I was a pretty hot-s**t diver in a wetsuit, then I got a DS, and I was an OW student all over again for how it messed with my buoyancy. Then I got pretty good at the DS, (or so I thought), then I took an unrelated (non-DS) class with a very experienced instructor while using my DS. I realized I didn't know s**t, and the learning curve of the "school of just diving and getting experience that way" was too slow.
I'm now taking a DS class from the same instructor. I'm sure it's nothing I can't learn over time, but the learning curve will get shortened dramatically.