I try not to change things up too much. I might widen my range a little bit. But I usually do that anyway, once I've established the desired image at the table. I might defend my blinds a little more. But in general, I'm not going to do too much different.
I've always been of the opinion that playing too many hands or too wide a range leads to bleeding chips. So when you do take down a pot, you're pretty much just replacing the chips that you bled away and not really growing your stack. Meanwhile other player's stacks are increasing and catching up to yours. But more importantly the blinds are increasing. And that should be your real concern.
Being at the top of the leaderboard is nice. And it does afford you the opportunity to be a little more creative and take a few more chances. But you shouldn't get carried away with it. Concentrate on quality hands and picking good spots and continuing to grow your stack, and the play that got you to the top of the leaderboard in the first place will probably keep you there. Then once you've made the money you can really open your game up and go for the win.