I don't have an experience with them as of yet, but BC's are probably what i'll go for. The price is good and they maintain the OEM separate spring, so there'll be no worrying about anything going wrong. If I had the money I'd be going for HKS Hypermax, which are around £900, or if I was really flush, KW V3's
As for the reinforcing, there are a few members who are running true coil overs without any additional work without any issues, but there's always the risk. People running true coil overs on some BMW's have had the rear shock burst through the turret