Ha ha, the everlasting issue of updating the A500/A600.
I'm not even going to begin on it.
I'm just waiting for Amiga-Digital to finish his prototype 030 A500, if that works you won't need any turbocard for it anymore and you won't need ram expansions either, because both will be availble.
If the board also can be outfitted with modern SATA and DDR ram, then it would be mindblowingly good, I guess nothing would top that, not even the X1000 or Natami.