There are so many choices of downpipe, fmic and exhaust. Do I spring for afe downpipe and exhaust? Do I go with vrsf and save money? I am wallowing in indecision. I found a blem ams fmic on eBay for 600 delivered but it says it does not fit 2011 e90s????. Do I spring for ets or er fmic or again go vrsf??? I would like anyone's two cents so I can weigh my decisions. Thanks in advance for the help.