Performance will be better without the DPF if the manufacturer has not considered the impact of the DPF but the gain is tiny. Your concern should still be the law and the environment, in any order you prefer.
The DPF has more advantages than disadvantages, for example protecting the environment versus a tiny performance gain. If you overcome the perfomance vs environment argument, then you should think very carefully about the legal implications if the law enforcement practices change.
If you are performance focused and you worry about the DPF, you will become better and faster driver by attending advanced driving schools and upgrade the suspension, tyes and brakes.
For a segment D car, the DPF itself is a minor gain for the more of 1.5 tonnes you have to carry around. Also, I am not sure how much you can push to the limit such a big car.
If you are interested in straight line speed and acceleration, you could investigate remapping the car but again be aware of the legal implications.
https://www.researchgate.net/post/Diesel_Engine_How_does_the_DPF_effects_on_performance_of_engineThis guy mentions that the perfomance penalty is 1% for every 3-4kPa of added backpressure. He mentions that a DPF adds 0.5-0.8kPa of backpressure out of the typical 10kPa for the whole engine. Assuming that the manufacturer did not really care to find other ways to reduce this 0.5-0.8kPa impact of the DPF, then you will gain a 0.16-0.20% of raw power. For the 185PS diesel that is another 0.37PS raw power at most. Remapping the engine, upgrading suspension, tyres and brakes, and continuous training to become better driver, will make a more noticeable difference than the 0.37 difference in PS.
The reliability is not affected by the DPF. It is just a filter inside the exhaust. If you try to remove it in the wrong way, you will create a lot of problems but this is not related to the DPF itself.