IMO, you have to decide how much you are willing to spend first.
Does the E9X kit use a beehive spring for the rear? This is what makes the TCKs unique for the E46s. Apparently a straight 60mm coil tends to bind since it is not spring on shock design in the rear.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red