Smurf, There will be a lot of different opinions about running a PCV with a flashed ECU, running a PCV may or may not be better and it is more expensive. I had my ECU flashed by Ivan, run a PCV with his map, performance and throttle response is fantastic. I did both the PCV and ECU because that was what Ivan recommended and I trust his skills. As far as I know Ivan is the only tuner who adjusts the cooling fans to come on sooner, which I like, especially around town. Take a quick look at your ECU for a sticker like many have suggested, quickest and easiest way to start and go from there.
2013 ZX-14R with lots of mods, quick and comfortable.