Will have to cheat a little, as I did do minor things to both these, but neither needed trigger fiddling, or regulator adjusting, "tuning" or extensive barrel massaging. Of airguns I've owned these two have been my most close to pure "out of the box" high level performers.
Taipan Veteran Short-reduced the hammer tension when received but otherwise shot it as it came out of the box for probably 3 years. Has since been rebarreled to a .20, as has been documented elsewhere here on AGN. Didn't "need" the rebarrel, I just wanted a .20 Vet and I love it even more as a .20.
Mac1 USFT-JB bore pasted the barrel about the same time i figured out the barrel prefers a specific lube so not sure the JB was necessary. Also added a moderator adaptor. Other than that JB treatment and the mod adapter, still shooting it as it came. It's been six years and I haven't been inside it yet.
Neither of these will ever be sold. They both shoot at that "special" level that ain't often stumbled across. Exceptional experience with both of them.