2 will present gains, but 1 is boosh in the sense of performance which really just get you in the practice breathing set up on a stock motor.
Examples include:
https://www.torquecars.com/tuning/tuning-stages.php
Upgrading exhaust for reduce in pressure + upgraded carb which leads to better off the line power base at stage one
(This is just general informal conversation correct me in qoute me if am wrong).
CVT UPGRADES are rendered usless without gearing upgrade in referance to two strokes, thus telling us the upgrades below stage 3 are useless in the 4 stroke world due to the fact that in the auto world 4 cylinder is the multiplying process by each piston. Timing, valve lash, stroke, piston deck, valve springs, and cam can also defeat it's purpose unless you want to spend $$$ on said upgrade to see true performance.
Improvements can actually be made in 2 strokes by running a hair richer which could only lead to fouled plugs causing frequent exchanging with additional emission output in the fouling process what you see out your tail pipe tip forms carbon from build up in the exhaust pipe known as sploooge.
In a automobile when the valve stems leak it is in 2 stroke stage of life at start up, when this happens it leads to the premature failure of 02 sensors which control the richness of the vehicle at cold start up much like the enrichner/by starter found on your common scooter.
Link .... Found here.
https://www.torquecars.com/tuning/tuning-stages.php
Not bashing, just would like to here about your intellectual stage for overall tuning.
