And a Anti Lift Kit IMO, Superpro or Whiteline, both around £170 plus fitting.
ARBS, H&R are a good choice, I have the Autotech and their bracket/bushes aren't very good so you'd be best to add a Superpro bush/bracket to both ARBS, another £100 ish on top of the £450 for the ARBS. IIRC H&R ones are less than £400 and their bushes are ok.
Engine mounts, Vibra-Technics. At least the lower engine mount and Dogbone bush, around £200. Add another £350 for side mounts plus fitting. Don't think THS do side mounts anymore.
You'll also need a decent fast road 4 wheel geometry set up.