I have two friends who each have the M3 and the S4, and coming from someone who has a really modded 335i, the m3 ate the S4 in every performance aspect (cornering ability, raw power, responsiveness, braking, etc) they are two different levels of car, in my opinion.
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2011 335i E92 - Retired
2013 M3 E92 - Alpine White/ Black Novillo Leather
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