Just a quick heads up on these.
We just had Tony M's bike in for what turned out to be a leaky front gearbox seal. Now we'd been through this bike 30,000km ago and that included a new clutch as the old one was 180,000 km old.
At that time we installed some 'Newfren' deep spline plates and they worked fine as a clutch BUT
on pulling the gearbox this time we found that the splines were showing quite prominent wear! Not as bad as 'Surflex' plates which can destroy their splines completely in only a few thousand kms but I still thought it was unacceptable so we replaced them with factory plates, (These used to be made by AP but the ones I just got from Europe were unmarked.) which although pricier are, at this time, the only ones I'm willing to trust.
The input hub was barely worn and although I would really of preferred to replace it I had nil stock, (Annoyingly one arrived in a parts shipment the day after we'd just secured the motor back in the frame
The long and the short of it is. If you don't rack up enormous mileages the 'Newfren' plates will probably be fine. My mate Steve has just put a set in his 850GT loop frame and I offered to exchange them but he declined because that bike will never see enough mileage for spline wear to be an issue. At least not in his lifetime! If though you do high mileages and red hard I would suggest pay the bit extra and go with the factory plates.
For Tony's bike I had to buy a set from John and Nicole at Motocicolo and the importer's price was a usurious $179 a plate, (From which I deducted the cost of the Newfren plates.) but the difference in price from Europe was only €20 or so per plate. That makes it a no brainer in my book.
(NB. The usurious price is no reflection on John and Nicole. That is the grasping claws of Peter Stevens at work!)