Any thoughts on Magnum Rotors
 

Like the ones listed here

eBay Motors: Magnum brake rotors BMW E53 X5 3.0i 4.4i 01-06 F+R (item 380112617819 end time Apr-21-09 18:23:59 PDT)

or these below

http://cgi.ebay.com/ebaymotors/BMW-X...3A1|240%3A1318

They look nice but rotors with holes in them stop less well than rotors that do not.

the problem I've learned (the hard way) with ebay rotors is the fans, or "vents" on the outer rim. On the stock rotor they are slanted and extend in for about an inch for maximum cooling. the ebay rotors (at least the ones I have seen) are just like a little bracket that do nothing. so they can potentially be worse than your non-slotted/drilled OEM rotors.

You can test them out, but @ $187 or even $245 for 4 rotors I would not expect too much quality. consider this, 1 front OEM rotor for a 4.4 is $120, and that's before dealership mark up.