how much do you gain with 202s over 188S?

You shuld take the question into the forced induction room. There, you'll likely find people quicker that have been there and done that rather than jumping into this thread with a question that doesn't exactly fit in with the OE posters question.

Also, in that room, there is a person that is in the biz of forced induction, SCDE. You could also ask them directly. There helpful and freindly.