I have an NZXT mesh, it has like switches instead of knobs so it's flush. Fits inside the door for my R4.
As far as fan controllers go I think they're mostly the same. Get one with enough channels and watts/channel for your needs. After that it's mostly aesthetics since it's on the front of your case.
You can get fancy but they're usually more money.
You could also get started on sleeving for around that price I think. Idk if that floats your boat.
A couple of fans is really the only other thing that comes to mind. How are your fans set up currently?
You could maybe get aftermarket heat sinks for mobo/ram/etc. A lot of that stuff is mostly for aesthetics though. I have the Samsung 30 nm ram, and it's pretty plain so I bought copper heat sinks and painted them. They were only a couple bucks each, and then another $5 for paint. It was a good way to spend an afternoon
