either maf or mafless really does need a tune to suit, just because a maf is kept dosnt mean it still knows what air is flowing into the engine for a desired situation and in a factory tune the maf is only solely used after about 4000rpm so under that where most of the driving is done u have a blend of maf and map so if the map reading is out because of the intake then it is still going to be incorrect so the fuel trims will be working to correct it, have a tune done corrects the AFR so the less the trims have to work the better the engine will run, not getting a tune wont hurt the engine it just wont be as efficient as if it were tuned to suit, fuel trims only correct a zone of map readings so the average of the STFT changes the LTFT zone to what it will correct too but in that zone u might have 50+ different fuel cells so even if some need less fuel and some need more they all get the same correction for the zone and thats where a tune can be cleaned up so it all works better
To give an idea my afrs were low 13s wot(not good -very very lean) stock map and had a bad hesitation around 1800-2000rpm.
Its not only the ve tables its ,a lot of others incl pe and dynamics and quite a few engine management tables.
Even cold start was too lean which I fixed.
Weather change its good the tune copes very well in the hotter weather eg 38 deg and above.
Some tuners pref maf you can do both, personally I prefer sd as its more responsive and fueling is very accurate.
I tuned my VF S1 in sd (mafless) and it drives really well and it will light up 2nd gear wot (auto) and didn't before (stock tune and maf).
Will put it on the mainline dyno soon and run it down at wsid.
Oztrack isn't the only one tuning VF commodores in Penrith so there are other options for those in the area.
https://www.facebook.com/CommodoreV8V6DelcoTuning/?ref=bookmarks