The short answer to your question is no, there is no MINI Guide. You already know the differences between the Cooper and S. As has been posted already, there are some basic differences from 1st to 2nd generation and even from early to late 1st gen.* Here are the major exterior differences. As others have noted, the front turn signals moved from the bumper on the 1st gen to the headlights on the 2nd gen.* At the rear, the 2nd gen turn signals are in the center of the brake light. The '02 - '04, the turn signal is in the lower outside of the brake light and the reverse light is centered below the bumper. In '05 - '06, the reverse lights are in the lower inside of the brake light. There are also certain editions that were available only in certain years. The most easily recognizable is the GP. It was available only in 2006. 2000 were built and only 415 imported to the US. The body color is Thunder Blue, the roof is Silver and the mirror caps are Red. The rear spoiler is much larger and is mounted to the sides of the rear hatch rather than the top. Each is numbered on the roof above the driver's door. The Laurel Edition is a 2nd gen all white variant with an off center stripe. It is on the passenger side for the R56-57 and the driver side on the R55. It has the John Cooper Works aero kit and matching stripes on the side. I am sure there are other differences and variants that I have missed. Happy MINI Spotting! Chris
There's a great (with pictures!) guide to the changes and different versions over at the MINI2 forums: http://www.mini2.com/forum/faq.php?faq=new_faq_item#faq_mini_generations
Surprised no one has mentioned the wiper mounting points. For me, it's the quickest way to tell the two generations apart at a glance. 1st Gen wipers mount to the body panel on top of the cowl. 2nd Gen wiper mounts are recessed below this panel.
ostcount Well except this..... I just look at 'em all and think, "Hell ya that's a bad ass little car! And I drive one." It don't get any better.
For me, the quick and easy way to tell a 1st Gen from a 2nd Gen is the side scuttles. 1st Gen is much more narrow top-to-bottom. No matter if it's a Cooper or an S, stock scuttles or one of the upgrades, the shape is completely different.