It seems that every time a new M car makes its debut, the desire for classic M, as well as their values, cars goes up. Newer M cars, with their bloated curb weights, overcooked styling, and lack of feel make enthusiasts pine for the good old days of cars like the E46 M3. However, getting a proper E46 M3 can be a bit tricky these days, as values are getting out hand and you don’t always know what you’re getting for your money. So Collecting Cars put together a helpful buyer’s guide to buying and bidding on E46 M3s.

To do that, Collecting Cars went to Everything M3s, a UK-based shop that made a name for itself swapping manual transmissions into M3 CSLs. It’s also started swapping manuals into E60 and E61 M5s. Essentially, replacing the much-maligned SMG gearbox has become the shop’s specialty. However, you don’t become an expert in doing gearbox swaps in one of BMW’s rarest cars without knowing the car like the back of your hand. So if you want to know, well, everything about M3s, that’s where you go.

There are quite a few things you need to check when buying an E46 M3, especially now that it’s quite an old car. Rust and corrosion are big issues in certain areas, such as the rear wheel arches. However, there are also some issues that seem major but aren’t, such as rust on the front fenders. While the the rear wheel arches require major body work to be done to repair such rust, the front fenders are bolt-on, so they can be taken off and replaced with brand-new ones from BMW. Shockingly, they aren’t even too expensive. Less than £1,000 can replace both, even after paint.

Another major issue that seems to happen with all E46 M3s is structural cracking in the trunk floor. I can even be a low-mileage car and still have cracking in trunk floor, enough to require reinforcing. Rear subframes can also crack, too. Then there are VANOS issues, worn differentials, and various other components to watch out for.

The E46 M3 is one of the finest driving BMWs in history and among the greatest sports cars of its era. Owning one is incredibly special and rewarding if you know what to look for and can fix any of its major issues. However, that can get pricey, quickly. So keep that in mind when shopping for one. And if you are shopping for one, watch this 52-minute, incredibly comprehensive video about the various checks that need to be made when inspecting and buying an E46 M3.