A german "tuning company" (SARO Exhaust) does the gpf modifications.
Their facebook post (translated)
"From now on we can offer you the OPF modification / deactivation for the Hyundai i30N / Performance without error message and WITHOUT an OPF deactivation in the engine control unit.
There are 3 different variants for the OPF modification:
1. Original OPF convert to dummy with probes modification for a faultless driving € 599
2.The OPF is replaced with a tube including probes modification 599 €
3.The OPF is rebuilt as a dummy and you can keep your original OPF course, including the probe modification 899 €!
[Source: facebook - SARO Exhaust]
I think it's quite okay, but not street legal here. I don't know in which country it could be done without getting problems. For sure your car will be a bit louder and get a different sound. Also the backpressure and the performance should be better after that mod.
"I" wouldn't do that at all. Maybe i would take another dummy or something like that if there would be no problems with police or insurance.
Btw, there are lots of people (exhaust modifiers) who do that stuff much cheaper. So that should be only "an example" because they've already done it for some facebook users^^