I've had a JB4 G5 iso (newest one at the time at least and still is i think minus the firmware upgrades that come out quite frequently which i did like). Now i sold the JB4 G5 w/USB & 2-Step relay when the MHD flasher app became more widely used and documented. I wasn't unhappy with the JB4 at ALL.. but i just wanted to try something different.
i flashed my car (with the JB4 removed completely from the car) with a V4 or V5 map 1+. It was basically the same as map 5 (auto-tune) on JB4, as far as power and drive-ability.
Now one thing i kinda didn't think about was that since i'm 6MT. I lost all the extra features the JB4 has like 2-step, NLS, WG Adj., etc. that the MHD did NOT have or does NOT have...
Not to mention the convenience of just adding a few gallons of E85 on every fill-up and have the JB4 Map5 Auto-Tune Map do its thing and feel that drastic power bump lol..
A little dissapointed that i sold the JB4, bc i learned that the JB4 could be stacked (BEF'd JB4 w/ MHD). That way i could of kept the cool features of the JB4 and still benefit from the MHD stock DME map/maps development.
Anyway fast forward to now, 1 year with the MHD now, and 2 years before that with the JB4 right before the MHD. I'm not happy or unhappy really. I'm still on MHD Stage1+. Haven't re-flashed my car for about a year. So i guess, maybe, I am missing out on the new MHD features.
However, I believe that there still isn't the 6MT features in the MHD app, that the jb4 had...
2-Step, NLS, Boost-by-Gear, and all the other easily asdjustable tables that the JB4 app had. Not to mention the other obvious features like On-The-Fly Map Switching, gauge hijacking for Boost/Timing/IAT...
I do have the ECS Vent Boost Gauge so that part is a little less important, but still useful/cool at the same time..
I wish i still had the JB4 just to try the BEF method and compare it to the flash-DME only MHD tuning. The JB4 App (PC) also had a GREAT logging tool i remember.
I would say like some have stated above, having them stacked is definitely a good option for those running ST on Port Injection or maybe even Meth Control. But also a great option for even a stock N54.
And to those saying that the MHD Flash Tool (app) is much, much more than a new style Cobb, not even close. If someone tells you that, just ignore them and google the information for yourself.
Since i've only recently done DP'S as far as power mods for a while (over a year ago). I havent bothered to re-flash any MHD maps or have a custom tune done. Im focusing on suspension/handling mods now that ive done all the Maintenance i wanted to get done. But soon i will be upgrading to a bigger FMIC, CP w/ BOV, Inlets, and possibly a LPFP upgrade to handle the E85 mix. Then i would go for the custom tune on MHD, but i would still be mssing some key features i miss, like i said before the 6MT features, as well as the E85 Flex-Fuel Setup that Terry@BMS i think is curently working on...
The reason im saying this is because some of this informartion could be outdated bc ive been out of the tuning research for a little, but i still do look forum topics on everything quite often...