Rigidity: Blistein or M performance suspension for m240i

[LamedonM]

I have sort of made up my mind, my m240i needs a more rigid suspension and spring. I don’t care for lowering. Blistein B12 sport line suspension kit for m240i would cost £764 to buy whilst BMW m performance suspension checked against my car vin would cost £1350.00 and it says only with springs.

Does anybody have experience of either or preferably both

Thanks

[LamedonM]

Is KW better than M Performance?

[LamedonM]

Will KW coilover street performance type be as rigid as M competition cars?