Juice

Guys/Girls

Im running Carbotech Xp8's all round on my STI (Brembo set up) with standard discs
(also have braided hoses and uprated fluid incase anyone does ask and the car stock discs have covered 22K miles

Now the problem -
I was out on Saturday night and driving in a spirited manner on private roads
on slowing down from around 15mph to a stop the front discs more especially the passenger side was grinding pretty bad.

Iparked the car up and looked at the disc and you can see a ring that runs around the disc which is roughly half inch in diameter on both discs, when you rub your finger on this bit of the discs its slightly rough comapred to the rest of the disc, now my question is WTF is that?....
this only happens when the disc is hot, and never does this from cold. how would i know if they're warped?

2ndly - I have options to change my discs to camskill ones for £70, re skim my brembos at £40 each plus vat, or buy godspeed discs 1 piece at £175 or 2piece at £325 (the new style groved discs)

pretty much confused on what to do and advice needed asap really

ps: the car is a street car and will rarely see a track

thanks in advance
saq