I've tested the Z2 against the OB2 and OB Classic Pro (now just OB Pro), as well as recently testing my 314-2 against a custom shaft and the OB1 and OB Classic. I have a very defined method of adjusting for deflection/squirt that's more accurate than most people I've run into, so when I test a new shaft I'm very sensitive to that. For the right shaft I would retune my adjustments, but I prefer not to...
The Z2, OB2, and OB Pro were very close in deflection. I noticed with the OB2 that the balls tended to be more center pocketed on the reference shots I use - in other words, probably a bit more consistent, maybe just a minor touch less deflection due to the lighter ferrule material. It also has a dampened feel, which some may like and some may not. Pairing that with a medium to hard tip can also help offset some of that mushy feel if one doesn't like that.
Z2 and OB Pro were very similar, slightly different feels and hits but so close that it didn't matter much deflection-wise, just personal preference. I shot with a Z2 for 2 years, I could easily switch to either OB2 or OB Pro with very little if any adjustment.
I now use a 314-2, and have been testing the OB1 and OB Classic. Similar results, OB1 might have just a touch less deflection due to ferrule, same dampened feel, both were practically interchangeable with my 314-2 on all reference shots I performed. I ordered a Schon-piloted Classic, I liked the consistent and stiff hit vs. the 314-2, and since it's starting to sound funny I suspect I have a small microcrack along a glue line, if so will be the third Predator shaft in 5 years that has cracked like that. They've all been replaced thus far, so no biggie, just been looking to try something else and also have a back up, just in case.
Hope that helps. I think you'll be fine switching from Z2 to OB without any major tweaks. If switching from an original Z, you'll probably find a bit less deflection with OB but something easy to adjust to.
Scott