2014 Mk7 1.4tsi 6M/T turbo upgrade options?

[ESSMAN]

Greetings all , I am speaking on behalf of my friend, who has a Mk7 1.4tsi bluemotion Manual with 70 000Km . He purchased the car not to long ago and after about a month or 2 he noticed a loss in power, He specifies that it feels like a loss of boost pressure , based on others he has talked to he believes that the turbo is at fault.

So this brings us to the question of this post, what are the turbo upgrades or sidegrades that can be swapped in and have the car running RELIABLY (his daily driver) and with a slight/ considerable boost in power from stock? My first thought would be OEM+ options such as a Polo Gti turbo since it is a 1.4 as well granted it probably has different internals. what are the options and what one might expect to pay, As well as any recommended shops to have the work done around the JHB area

Additional questions we have are , How much power can the platform take reliably before things start to get expensive ,ie how much can the stock 6 speed manual transmission take , how much power before the diff and other drivetrain related parts start to fail.

alternatively to all of this would it be recommended to just rather recondition/replace the stock turbo and maybe tune the software, exhaust etc when it comes for best bang for buck.

all information is highly appreciated.

[mk2-phreak]

Sell car and buy a GTi