I'm picking up a CPO MS P90D this weekend (excited!) which comes with 19" slipstreams. I'm looking to buy 21" cyclones as my summer setup and keep the 19" set for winter. Does it matter if I buy a square or staggered 21" set? The P90D is a refresh model if that matters. Also, anyone have experience with Auto Rim Shop? They are selling refinished cyclones at a reasonable price. Thanks!