I'm on my third gen 4 zx-10r, the first two (circa 112,000 kms across them) had PCVs and this third one, which has done circa 147,000 kms, has had a Woolich flash from close to day one.
All of these bikes are for street use, with occasional track days.
Night and day. Simply night and day. I would never not flash a future bike.
Of the two options, mail in vs self flash I'd always go with self flash. Why? Because you can flash it back at the drop of a hat, you can tweak it as much as you want to perfect your own unique tune. Two bikes coming out of the factory next to each other will require different tuning, that's just the way the world works. No two bikes ever benefit from exactly the same fuelling. Doing that is always a compromise. Useful too if you get an EPA type notice too. And if God forbid something happens to your ECU in the mail then you'll be up for a world of cost with a new immobilizer etc.
So. Go self flash. Is it hard, no. I've written several articles on how to use this, these are stickies on Justin's Woolich Racing Forum and are also hosted on my personal not for profit rider website https://www.arcnineohnine.com
(hint, under "articles"), direct links below.
Right, now you've decided to self flash with Woolich, what will you get out of it? As near to a perfect tune as you want. Removal of fuel cut on decel, one of the very worst things ever done to our bikes, no need to add block off plates (which are seriously fiddly and very time consuming to install), no need for a resister pack to allow removal of the exhaust exup valve and perfect fuelling. So what? Perfect fuelling, who cares? To give you an idea my 2nd gen 4 with PCV would get a *maximum* of 200kms to a tank, my current one gets 240-280kms to a tank. What else? Smoothness. A beautiful tune lends itself to a beautifully smooth throttle feel.
Have a look at
Happy to answer questions on this as I've been there since Justin released his very first flashing kit for the gen 4 zx-10r over six years ago. I prefer to answer questions in a public forum so that others can benefit.