ok I have heard of
rb 2.2, = tomei larger pistons only
2.3 bigger pistons 81-81 mm with rb25 crank and rods
2.4 with the tomei pistons and rb26 crank and rods there is machinig requiered but not sure what
2.45 special hks cranks rods etc and dispalyed on my site
do a search on the sdu foums it has been disussed heaps personally I would only do the tomei pistons or copies 82 mm cause I know some one who made around 600 with this combo.
and decided againt the 2.4 kit cause and rb 25/26 was chaeper this was in japan
meggala