I doubt it makes any difference, other than having additional brake piping need to be made up.

Yes!
I got hold of a set of police front brakes for the yellow S1 in my Avatar, they were definately single pipe, as they fitted straight in with no mods, and they were good.

I have purchased a set of jag brakes and they are single pipe,my vitesse is twin pipe.I think to complete the conversion i need a normal pdwa valve. a set of rossini jag discs should look right on it too.The obvious advantage of the jag brakes is in the swept area,being about 50% greater,not in the pipe arrangement.I would go with the twin pipes as it will probably save a bit of work.

Rossini jag discs 284mm are actually cheaper than the rossini 258mm vitesse discs .Mad eh!

£220 quid vitesse discs as opposed to £149 jags.car parts direct under the rossini heading.Dont know how good they are but they dont half look nice

what is the actual advantage to having twin pipe brakes? why did rover decide to use them in the vitesse/vdpefi?

Maybe the twin line brakes were that little bit safer? As the Vitesse/VDPEFI had a more powerful engine? Is just a shame Rover couldn't have spent a little bit more & put some discs on the rear too.....

I think only reason might be to get smoother operation from other side pistons and so the pistons wont seize so easily.

Or maybe they just needed to fit a twin pipe system so they could homologate it for the racing cars? Similar to the (welded up) adjustable rockers.

No advantage on the road but a very nice one on the track perhaps.

There were twin pipes on rangies also?

Hows the brake conundrum going 5000?im going to have to buy a new pdwa valve for single pipes.Not yet bought rossini discs though,got to crack on with the axle.JJ

are you in the cluband also if you are putting together in the spring try to coincide it with spares day 1 at rimmers.This might save you a couple of quid.