Arm suggestions for my Basis 1400

Currently I have a Basis 1400 table with a RB300 tone arm (stock cables). My cartrige is a Micro Benz MC20E2. I only recently got this first turntable (barely used for $1100) and I wanted some suggestions on a better arm/cartridge combo I could upgrade to. I was thinking about upgrading to a RB900 tone arm with cardas wire and a Micro Benz Ace cartridge. My preamp is a Ayre K-3x (amazing phono stage).

Please help out this vinyl newbie.

Thanks for the suggestions.

Why not get Origin Live to mod the RB-300, sonically at least, you'd be ahead. If you have a little more scratch, the Basis Vector or Graham arms are excellent matches.
What Viridian said.
TWL as the resident Rega expert have you had the chance to audition the RB-1000 yet? I can't find one to audition here in Portland OR and am quite interested in how it stacks up.
Viridian, no, I haven't heard the new RB1000 yet. However, on the Rega website, it states that it is simply another refinement of the RB300 design, with better bearings and more hands-on adjustment and quality control. I think that this would contribute to the sound quality, and would expect that with the already excellent basis of the RB300, and these added improvements, that it would be a very good sounding arm. I'm looking forward to listening to one.
TWL, I too saw it on the website. The proof is in the listening though. Sometimes the smallest changes make, to me, what is night and day differences and then sometimes what look like massive changes make no difference at all. If you get a listen please contact me directly and tell me what you think.
Decided to get a new cartridge for my Basis Table. Just got a Micro Benz Glider 2 installed on the RB300 arm. This cartridge makes all the difference in the world. It is still breaking in though. I also aquired some Cardas XLR-RCA adapters (MUCH better than the ones I was using before).