Some sleuthing revealed
THISI've got a nice fuzzy feeling that the RX7's do have carbon seals.
The turbos are both Hitachi HT-12's. One has a 51mm 9 blade compressor and the other a 57mm 10 blade compressor wheel.
I can't seem to find any datasheets though but I reckon these might be worth a play, especially since we're talking low cost here.