My other car is a MINI!!!!
Dan, mate, we've been through this old chap.
Eibachs are the ONLY way to go....
H&R have clearly made a massive cockup and offer a 26mm front bar witha 22mm rear bar, these don't corner NEARLY as well as the eibachs with a larger rear bar. it stops body roll, but keeps the ****ty understeering nature.
Again, the KW's Tom suggested are a bit big on the front at 25mm, it's just not needed.
Basicly, you need a larger bar on the back, i believe neuspeed do a 28mm rear bar, but that's pretty hard core.
Eibachs are the most tried and tested out there, and by far the best too.
If you need convincing, feel free to come down for a ride some time soon, and you can take my car out for a drive