If you want some random general info about the JDM engines... EJ20G/K/R/7's are all great engines to use if you want 2L turbo (JDM turbo).
EJ20G's come from gen 1 legacy RS/GT's, and version 1/2 wrx/STi's - these engines have very strong closed deck blocks. Also, unlike their US counterpart (the EJ22T), the 20G's are DOHC and intercooled (Water to air intercooler).
EJ20K's are open deck, and come from V3/4 STi's. They are very very good engines, simple yet effective. They are OBD-1 ECU controlled, can be modded heaps and will still run perfectly on the simple ECU. No TGV's or EVCS or anything fancy - they're just a pure engine which i love.
EJ20R's are the Twin turbo versions of the K's, that came on the gen 2 legacy GTB/RSB's. They have the same injectors, loom, and everything. The R is reputable for blowing big end bearings though - well worth buying, then rebuilding.
EJ207's are the V7+ STi engines. Have semi-closed-deck blocks.
The R's and K's are essentially the same, only the R comes with twin turbo gear which you will need to swap with single turbo stuff (do NOT even consider twin turbo...) The benefit to the R is that it's cheeeeap, but just as good as the K.