Highly reccommend one of these. Very useful
http://www.drapertools-online.com/b2c/b2citmdsp.pgm?pp_skmno=59258
Machinemart also sell some good kit
I'd be wary of the draper torx set - they're the hollow security key type and one of mine snapped leaving me with a right mess to sort out on an engine bolt. They did replace it but I'm a bit more cautious when using them...

