Ok so I’m going air filter crankcase filter block off plates ecu dyno pcv?
Make sure you can do the PAIR removal/blockoff plates mod on the Gen 2 ZX-14. I could be wrong but I thought that was not possible on the Gen2.
Go with an aftermarket air filter if you want but it will only give you a couple hp on the very top end and probably won't impact your AFR at all.
Most flashers like you to have the PC5 on there to tune fueling so go with it as your tuner recommends. Go to a reputable tuner or don't bother. The dyno session will help but I doubt it will be much better than a good map from Guhl or someone like that.