What is Harder than Gravity?

[Gigas]

I've been playing FFR/DWI/SM for about 6 months now, and I'm now at the point where I can get a C somewhat regularly on Gravity, no mods.
I'm obviously going to get better at it over time, but once I A or AA it, I need something new to challenge me. I'm not one to try to AAA everything, I simply enjoy beating it. I know of no other songs that are harder than Gravity either, so I'm kinda stuck. I've downloaded all of BemaniRuler's DWI files off bemanistyle, but the only "new" one I found that comes close to the challenge of Gravity is "G2". "V" too of course, but I had it already anyway.
Nothing on FFR is that challenging either really, it's far too "random" for me, things get offbeat too much, and it's skippy on the FPS far too often for me to enjoy any of the harder songs (even tho I run a 1.8ghz with cable modem). Ronda Alla Turca (spelling?) Slows my FPS down to like 9 on the runs, which is just stupid in and of itself, even more so considering no other song does it.
Well, to cut through the BS, what is harder than Gravity that I can find on DWI or SM? Preferably DWI--I prefer it for some reason, maybe it's the 400+ song list I have on it.