Well, I'm betting removing a DPF is illegal. The
ECU in your car being replaced has nothing to do with the DPF. Provided you're not driving short distances where the engine does not reach full operating temperature, you shouldn't have any trouble. If you do, you just need to follow the process when a message appears on your dash.
I had VW, that at the time, DPFs were not a requirement, but you still had to be floor it once in a while to blow out the soot. The result was black smoke out the exhaust pipe, which I'm sure was not good for the drivers behind.
DPFs are there for a reason.