got some 13" brembo lotus kits from stillen (ipd used to carry them, but due to lack of interest, they stopped)...it's a 4 piston fixed caliper up front. u've got the oem set up backwards, the front is a single piston sliding caliper, while the rear is a 2 piston fixed caliper (opposing); both made by ate. fhd16 on volvospeed.com has managed to put porsche 993 twin turbo front brakes (developed by brembo for porsche) on his 95 black t5-r. the red calipers run a nice contrast on his titanium grey wheels and black car. my lotus kit has black calipers, and the rotors look a bit busy. there are some other tuners out there, like eurosport tuning, who i believe carries ap racing 4 piston 13" front brake kits...there is also tar ox, making 6 piston calipers. u can check out http://www.volvotuning.com/scripts/parts.php?brake_kit for more info on brakes. as for the 850r, it should be stock ~11 in up front, same as turbo/t5...i have heard the front on some euro and police spec cars had larger front discs using the same caliper on some of the v70r or even s70r (europe). do some searches, it's bound to come up. the rear is another story. for some reason, they used only non-ventilated rear rotors...i have yet to hear anyone upgrade the rear other than keeping stock size, using aftermarket same size rotors (be it slotted or cross-drilled) and some other pads... even now, the rear on the 2002 v70 is a single solid piece, not ventilated...

here's some of fhd16's pics...i'm still waiting to put mine up...