the inner steering rack joint is exactly what it is it is on the steering rack but on the inner sides closer to the rack assembly, the inner cv joint is on the drive shaft closer to the gearbox than the hub... don't confuse the 2, they are completely different parts and as such there is a price difference between them...

I suggest you look at ECP and look up both parts using your registration number... you'll see the difference between the parts immediately.. and there might be a difference between the drive shafts but definitely not with steering racks joints.