u NEED research Stingray first.
if i research and buy stingray before april 15th, i can buy m1128?
Sure, u not can buy the m1128 if do it after april 15.
After aprill 15, just can buy the M1128 after research Stingray and m1296.
I have exactly the same issue. With every update they switch vehicles and move new ones in. The grind gets harder and harder.
In my opinion Gajin does this intentionally to force you to buy you through the techtree.
Regarding the change of vehicles to different tech tree lines, I prefer to research the vehicle I want as soon as possible before any update is released even if it means sacrificing some time during those 2 to 3 weeks of dev server previews showing what’s coming in the major update.
Of course, I understand that not everyone has the same amount of free time, but I doubt everyone can grind nonstop for hours just to get that extra 10% to 20% research bonus from using the previous vehicle in the line.
For those cases, I recommend committing your time to Gaijin: focus as much as possible on grinding with either a premium vehicle or the previous vehicle in the line to take advantage of that free research bonus.
And of course, avoid using jets/aircraft in tank battles if your goal is not to research them. You want all possible RP going into your ground vehicle, so play tanks.