If you want that Systemdek II to sound it's best you have to puchase one of the acrylic platters for it and use a Rega RB300 tonearm or better tonearm and a real good MC catridge. YOu don't need any mats with the acrylic platter. The unit is almost as quiet as the VPI 19 MKI or MKII. The MK III IV and higher and the Aries and scout series are simply better and maybe not by that big of a margin. Blacker background, deep sound stage and the Rega arm makes this table handle a variety of cartridges better than the lousy profile arm.
We put several expensive tables during the 90s up against the Systemdek II with the acrylic platter Rega arm and AT OC7's, Vandenhul MC1's Sumiko Talisman S etc. All low output MC's and they performed wonderfully. It shamed several tables 3 and 4 times the price. Kent Brandsford of Hi Fi Heritec touted the Rega and Systemdek combo as one of the best value systems money could buy.
I'm using a Systemdek IVe with a Rega RB600 tonearm and AT OC9ML and Dynavector 10x5 and I'm very happy with it so far. The !0x5 is only a month old and not broken in but sounds pretty good. May not be as good as a Lyra or Benz or Ortofon in the 3 to 4 k range but is about 90% of what the others deliver IMO. I have owned Sotas, VPI's Oracles and other tables and I hold this Systemdek near my heart. If I were to step up it would be a Scout, Aries, or a table costing 4 times more but I'm not sure they will trounce the IV. By the way the 4 has a nearly a 12 pound platter vs the IIx 3.5 pound platter. Heavier springs and bigger armboard mount. Your II is a great table with potential if you are willing to tap into it! A guy sells the platter on ebay. Oh, Audionote sells a version of the IIX 900 called the TT1 for about 2 grand. Acrylic platter, rega arm and a square armboard. check it out and they sell the acrlic platter for the IIX too I believe.