I have been looking to buy some wheels on craigslist for my silverado. I know I need size 6 on 5.5 (6 139.7) but someone told me to beware of the bore size even though the bolts match up. How am I supposed to know what the bore size for all the wheels I am looking at? The colorado wheels I am looking at have a 106.1 mm bore. What does all this mean for the average Joe like myself?