Pescaras are problematic.
Had a used Porsche BBK for my standard eddy, needed spacers, 10mm I think. Still have tnem in the shed somewhere....together with the necessary longer wheel bolts...
That setup didn't work out for me, due to issues with the seller sendng me bits from a mixture of BBK's! I wasted a lot of time and effort....
So, I bit the bullet and brought a new Stoptec BBK (ST 41 I think) off Awesome. Not a bad deal in one of the sale events.
These are basically American licensed Brembo 4 pots, and fitted very easily, no spacers.
Delighted, they are very light, and do all I want/need.
Done 20k on the riad, no problems. I keep a spare set of ST oem pads, they are available for £65.
I have grooved discs, but be aware that another guy on here had the same set uo with drilled, and they cracked. Changed under warranty.
Full details already posted if you search.
Spacers can be OK if done properly, but 20mm too much imho.