And I agree with Barton, Tiger is a shitty tank and definetly not a shock unit.
And with this, I think it is possible to say that T4 does work in 1v1. Knowing this I would actually rather tech, build T4 and make a Panther than wait for 720 MP (?) to trinkle into my bank.
I think gradually spending MP and Fuel (in this case) with teching is safer than saving up for a tiger that really isnt that good. And then you have a Panther!
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If you manage to tech to t4 before an IS2 comes out you are in a really good position. That is also because you know he had to really commit the MP and Fuel to get it out.