to be honest I am not convinced about coilovers.
You need to reinforce the damper mount to take the coil over, as this weight of the car is no carried there and not through the rubber donut and hilo/alu trumpet.
Rubber donuts, and supplementary dampers are tried and tested, and work well. For a road car i would go for the standard rubber donuts as you already have. And something like the kit you posted.
You could change the rubber donut to 'coil springs"
http://www.minitastic.co.uk/home1.htm, which basically just replace the donuts.
However for a road car i would probably keep the standard rubber donuts.
Think about subframe mounts too, if you want to go mad!
I have on my mini (not bought as a kit)!
http://www.minisport.com/mini-spare-par ... P431A.html I went for these as they are adjustable, I have 13" wheels and had them set by a mini garage in London to 1 degree negative. The other arms are fixed at 1.5 and 2 degrees negative which i was told was too much for 13" wheels
http://www.minisport.com/mini-spare-par ... 0512.html- heavy duty a must!
Poly bushes - but i have 3 bushes on the tie bars (1 soft rubber one on the outside before the poly bush) I was told this would help brake weave - an explanation here -
http://minispares.com/Product.aspx?ty=p ... 257&title=
I have the cheap hi los and standard rubber cones.
I found that the dampers needed to be changed now too as the car has been lowered -
http://minispares.com/Product.aspx?ty=p ... 960&title=