I'm probably going to order a Steeda timing adjuster and pulleys very soon, but am a bit concerned about the air/fuel mix after advancing the timing. I'm planning to try between 13-15 degrees of timing (this seems to be the norm before detonation for N/A GT's), but don't want the car to be running too lean/rich. Should I be concerned? Also, has anybody tried the UPR or BBK timing adjusters? Just wondering if they might be "better" than the Steeda part. Thanks in advance!