a question that will result in 20million answers
answer 10 million, mine, is the following:
for value for money the s3 nova. it is quick enough for small tracks, large tracks, and has the benefit of machine internals.
the jps3 is good, but only if you are racing on a HUGE track with top, TOP (as in top ten in your state) champs.
a good driver will do the same times with both these engines consistently. and a great driver will extract the extra "poofteenth" out of the JP.