It's not a club or anything to do with what brand the turbo is, it's having a big useable power curve which makes a car more driveable on the road.
If a car is still in full standard guise, full interior, not stupidly noisy and could be driven long distance in relative comfort, and have a power band that is big enough to be driveable then I think it's fair to say it's still a road car.
my cossie in its old spec was in rods own words not a road car anymore as it was a pig to drive, had to be thrashed to the absolute limit to be able to shift and get back in the power again, hence changeing the spec for the road which is where it's at now, a gtx4202 and race fuel was going to be used for the top speed it was going to do

But it is solely a road car now hence being tuned on pump fuel no racegas or nitrous

My new gtr I have used on the road but I wouldn't class it a road car, huge amounts of transmission noise, deafening exhaust, gearshifts set up for drag racing are very harsh I'd not want to long journeys in it would do my head in nowadays 🤣😂 lol

It can be driven on the road but it's certainly not what I would call a road car anymore it's to extreme.