i ran a 15.7 with just a 5zigen exhaust and butterfly/resonator removed. i had 90k miles on my s13. i shifted at 6200ish.
speed up your shifting and you'll drop your time more than just thinking about what rpm. slow shifting adds a lot of time <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/tounge.gif" border="0" valign="absmiddle" alt='
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