regualator for a NA engine definately useful while only u install it and dyno it to adjust it below its my own exp
i am driving 6a12 mivec manual, change hks open pod, 2.5 inch middle piping and 3inch straight flow exchaust.i install a regulator in after12 cost me rm450 total the brand is works,and they had adjust for me without running dyno,after i install it i feel i am losing power on top end,and not much diffrent with and without it,
then i go to under 5 subang(workshop recommand from my brother),i go for dyno dynamic(they claim 20% tension then dynojet),first of all while on the first run of dyno,afr reading dile 10.1 its too richhhhhhh,i get 118whp
so after a few runs with adjustable the regulator only my afr become 14 for idle 12 for wide open, and my perdana get 140.8whp,its mean i get more fuel efficient and power almost 20++on wheel power just for fine tune the regulator, forget to said i am using ron95 petrol only,for the 20 whp more,i feel my car lighter(rev easily get red line) and more fuel efficient.
and i did ask the workshop should i go for e-manage,they said no need for stock car,and even with the e-manage,its not help lot,if really want to install that kind of things, go for haltech.
what i said a patient tunner is very helpful.