Vialle & Prins are 2 big players overhere. They did some testing on TFSI engines and did not (commericaly) go on with it. Due to cooling you still need 25% petrol injection (ecu doesn't like this and creates lots and lots of errors). Besides that, engine wear increased a lot. Don't put your GTI on lpg/lpi.
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Did some further research, R32 is no issue. They offer a kit for the more recent TSI engine, but not for the TFSI one. Anyway, unless you have an R32, stay clear!