I don't know about the Lambo setups with a nearly 50mm diameter diff front to rear..based on all the research i did across multiple car forums with awd, the concensus was keep it to 1% difference and possibly as much as 3 %. all I wanted to make sure for my 600 is that my overall rolling diameter was as close to the same as possible and avoid the risk..especially being in warranty. Some of the IS guys reported issues with non matched overall diameters on their staggered but who knows what exactly caused the issue. You ran on that setup and seem to have had no impact that you know of and thats great but I wanted to keep overall diameter as close to oem specs with plus sizing and balancing proper load rating along with it..255/30 and 305/25 takes care of that for me and you will enjoy it too..plus to your point..looks much better