I went from stock to 3.73's shortly after I installed the S/C. Some go with 4.10's but it is my opinion that for a daily driver 3.73's are the perfect combo. If you are going to spend a LOT of time at the track then 4.10's or better may be "your cup of tea".
I opted for a roots blower (Allen), with them, you don't have to worry about "keeping it in boost". May be worth considering. I've been getting 27 MPG Highway lately!! Though, I have bought 3.73's to give me a little more response, just have not installed them, yet. I think 3.73 is best "all around", but OGBATMAN's 3.90 idea is certainly a good compromise as well.
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