Hi there. some information that you might have already read from otheres:
Stella SW20000PG (Power Gears) is the Japanese version of 20000FA (export version), both are slower retive ratio for jigging and deep fishing.
Stella SW10000HG (High Gears) is the Japanese version of 10000FA (export version), both have higher gear ratio for popping.
The difference between Japanese and export versions is not in the reels, reels are identical. Japanese versions come with an extra spool (worth $200 if bought alone) and two bottles of original shimano oil and grease (worth probably $50?).
If you are asking which Stella (meaning it must be a Stella), then I suggest SW20000PG. You can always use extra effort to wind faster when popping, but if you get the higher ratio (SW10000HG or 10000FA), you will lose winding torque that you can't compensate for manually, especially when reeling in a heavy fish from the deep.
If it does not have to be a Stella, then my first choice would be Daiwa Saltiga. I have both and Saltiga is superior to the Stella in many aspects; stronger gears (bronze+steel vs Duralumin+brass in stella), better sealing for drag and gear box, much smoother under heavy loads, and it seems to handle braid very well. The new $900 Accurate Twinspin gear box is a copy of Saltiga's, not Stella's.
I wrote this last weekend, you may find it interesting http://www.caranx.net/forums/index.php?showtopic=3128
Good luck with your choice