They will do nothing to the speedo if he uses the correct size tire: 245/30-21 or 255/30-21
Front and 295/25-21 Rear.
The stock 7 series tires are: 245/35-21 and 285/30-21 which are about 4% larger than OEM 6er tires. Not a huge deal but your speedo will be off showing 4% slower than actual speed.
You will need 10mm front and 15mm rear spacers. 20mm will probably be OK with a more aggressive "pushed out" look.
Straight lines are for fast cars...turns are for fast drivers
'04 M3 - track
'06 650i Cab - daily driver
'02 Highlander - kid hauler
'01 330Ci - winter beater
Last edited by Yorgi; 12-25-2012 at 09:49 PM.