Fidelity Research 64s vs Jelco SA-750e


Currently I have a Jelco SA-750e (10 inch) arm on a Sota Star Sapphire with a Koetsu Rosewood Signature. This runs to an EAR 834p, Thor TA-1000 pre, Quicksilver v4 monos, and Verity Audio Parsifal Encores. The sound is very good now, but I wonder if I could decrease record/surface noise and increase bass and dynamics with a better tonearm.

Obviously the Fidelity Research 64s is better than the Jelco, but can anyone offer opinions about what kind of differences I might hear and the magnitude of difference, if I change the Jelco for the FR? Trying to decide if it is worth the extra $1300 or so to upgrade.

Thanks everyone!

montaldo
I owned both the Jelco 750D (9-inch) and the FR-64S played with my RSP. The Jelco was tweaked with the old TTW VTA collar which, like the B-60 base, adds even more weight to the arm. The FR-64S was without the B-60 Base. Head shells were Yamamoto HS-4 (Carbon Fiber), HS-6 (Titanium) and Ortofon LH-8000 (Laquered wood).  
In my system, the overall difference was small with the edge going to the FR-64S.  The FR with the LH8000 had the best combo of bass extension, midrange beauty and extension on top. Perhaps the difference would have been even greater with the B-60 base but it was enough that I was happy to sell the Jelco and do not miss it. I think the difference is small enough that you can take your time to find the right FR-64 (condition wise) for your table. 
Though I haven't had a stock 64S base, I'd agree with chakster that the stock 64fx base is really nice and solid. It's also very easy to dial in VTA with this base - not as easy as with a true VTA base, but easy enough unless you like to change VTA between records. 
This is great feedback! Exactly what I had hoped for. Karl_Desch, what a break for me that you have experience with both of these with a  Koetsu. Thanks so much.