As it increases the caster angle you might find the car following ruts in the road, etc. but its not that bad. Mine does it, others may not but you just correct it and carry on. In theory more caster will make the car harder to steer, but the 'R power steering sorts that out nicely 8) .
Another benefit to the kit is it adds negative camber when you are cornering, so you don't need so much camber angle when the wheels are pointing straight. This reduces the shoulder wear on tyres that mega-camber will cause.