Yeah mine ate okay not brilliant could probably do with new front calipers the pistons are pitted and didnt know wether to try vented to see if it improves the braking
make sure your brakes are 100%, no seized pistons and your should be ok with standard brakes, vented are for preventing brake fade, round town there should be no difference in performance between those and solids,
Remember they are only vented to let heat off. How often have your defender brakes got that hot (because your going so quick of course!) that you need vented disks
If your running a 90 I wouldn't bother.
To go vented you need to either get the spacers and split the callipers. Or for all it's worth buy the wider callipers.
Yeah im gonna stay standard get new calipers and pads all my brakes are muddled up with the incorrect calipers so im gonna try find what calipers are best to get and get it all sorted as last time I orded pads nothing matched was a nightmare