i went from a RST to a 4x4 stage1 and it was a great move the cossie is a lot more refined drive wise, plus when i went to stage3 it had decent power.
It is costly when things go pop tho, i had 1 engine meltdown, 1 cambelt falure and other bits, at the mo i have an S2 again, purly a track car, thinking about binning it for a 2WD tho