You can run either but map 5 will probably give you a little more power than map 2. And all maps take into account E85 content and adjust to a certain extent. But map 5 is the map that is basically made for E85 usage. Did you get the JB4 G5 board or the regular JB4 G4? Map 2 targets certain boost targets while map 5 autotunes to make your own, i guess you can say "custom boost targets" depending on your mods and octane. It also adjusts to the current temperature outside, how dense the air is ect... Map 5 is a safer map to run for sure. Especially if you dont have the supporting mods. The stock intake is pretty good so get you some good downpipes and throw some E85 in there, set it to map 5 and your car is going to transform lol. def get an intercooler too because most all intercoolers reduce intake air temperatures when your doing run after run which is good for the turbo's. Your about to have some fun my friend
A/W E92 335i M-sport with JB4 G5 ISO/ E40 WEDGE PERFORMANCE BACKEND FLASH, Alpina TCU flash for AT/Switch-tronic +AR Downpipes, Stett gen 1 intake, Wagner-Tuning FMIC+RB Turbo setup/ RB PCV Valve+ Akro exhaust+60% E85/93 mix,+ HRE P40S wheels, KW coilovers, M3 sways,+BMW performance CF Mirrors, BMW Performance CF deck lid spoiler,+ CF interior trim, p3 vent boost gauge,+ LUX angel eyes (11.73@119mph on street tires) NO METH!