twin scroll are commercial turbos small rpm range they need to spool quick for more power,
petrol uses a bigger rpm don't really need twin scroll, as what you pic up bottom end you will lose top end as the restriction in the housing just like using a smaller turbine ,

what i'am tring to say is a .86 twin scroll will spool quicker than a single entry .86
but the single at high rpm will make more power [not unless you've gone too big on the exhaust housing then twin scroll will be better as its so bigg that there going to be no restriction top end
and will spool a bit quicker but it will be really fill bigg]