you can adjust timing, i did a 2* bump on my timing when i was at uprev in austin a couple years ago (significantly reducing spark knock at idle instantly). that sounds about right as far as what all you can adjust. the only thing that can't be adjusted (as far as i know) is the VVEL system. an email tune will definitely be better than no tune at all but a true custom dyno tune for your engine and mod setup is the best option
