Why not just hubs in the rear?

[Lair]

I sold my 325is, but I've found a 318 vert that I want to build. I wanna do a 5-lug swap first.

Can anyone tell me why I can't just exchange rear hubs with a 318ti? The trailing arms interchange, so why won't the hubs fit the e30 trailing arm?

[matt]

They probably will, I know the e30 M3 ones will swap right on.

You will also need brakes from the car you're swapping from.