This is purely just an observation on my part, but where the two upper tubes go forward for the upper A arm mounts, the front of the main frame is very rigid. The upper A arms on every bump are pushing inward on the full length of the upper tube all the way back to the main frame cross tubes. It's right at that point that the frames are cracking.
Even with the new reinforcement tube and gussets, the front upper A arm mounts are still going to be pushing inward on every bump and flexing the upper tubes.
If you look at the pictures of the Liberty Ace, it uses a similar tube main frame with the forward tubes for the upper/lower A arms to mount to........ but they have an upper front cross tube that bolts into the front of the upper tube which gives that whole upper tube assembly a box like strength rather than just cantilevered forward tubes on the M3W from the main frame tubes.
The Ace used this same bar to mount the headlights, the ole two birds with one stone approach.
My gut would still say to have a tie bar on the front would be a better solution rather than beefing up the cantilevered upper tubes back at the main frame tubes. The tube could easily be a bolt in and it could be chromed and used as somewhat of a "crash" bar for motor protection as well. Just a thought.
