Questions about build direction in 2014 VW Jetta 1.8T

Good afternoon everyone,

I am reaching out in regards to a number of questions I have that I am really just unable to find the answers to. I currently own a stock 2014 VW Jetta 1.8T EA888 3gen and I have been torn in between building up the Jetta or getting something else to build. I want to say that no matter what direction I go I do not intend to sell my Jetta since it has less than 60k miles and is paid off. I have been reading that the 1.8T can handle some where around 300-350 HP on the stock internals with the IS38 Turbo and other supporting mods. I have not been able to find anything about what the 5speed manual transmission is able to hold. I know that pushing anything more than 300 HP I would want to replace my clutch. My goals for the car is to be somewhere between 400-450 HP and I have no issue buying a 3rd gen EA888 2.0T and building it to hold the power. My only real question I have is if my trans can hold that power or if I will need to switch to the 6speed? Could the 6 speed manual hold up on 400-450 HP? I know that people have accomplished well over 500 HP out of the EA888 2.0T. I am mostly just looking for information on the trans I currently have and if I would need to swap or even build up a transmission to handle that power.