The 370 is an evolution. The 350 was a revelation because there was a drought of focused JDM sports car since the death of the 90s halo cars. Also the 350 had that initial torque rush with the DE that is no longer present, it's as flat as our interstates.
Still, the engine has the high end that was severely lacking with the DE and that annoying damping bumpy suspension has been fixed with the 370.
The 370 is also more rewarding to unlock. It would of taken something like a v8 or forced induction to really set the car apart from the 350. One thing it did do IMO was make the 350 look dated, which is an accomplishment given how fresh that design was when it hit.
For the 350 guys like myself we just need to unlock the 370!! The most important part is the price is right, some major issues have been taken care of, and it still retains its Z aura IMO