You answered your own question:
Get a wheel alignment so you get measurements
This will tell you if you need adj castor and camber bushes = very likely
Steering rack has nothing to do with it [unlikely anyway]
Get the kit , fit the kit, get another wheel alignment and jobs done.
Whiteline make all this stuff, as do a couple of other brands, I'd drop SK a PM and order a kit, you'll only chew through tyres like there is no tomorrow otherwise.