I came from a 335 to a R8 V8 and now to a V10 Spyder. I'm sure that the M3 can keep a pretty close pace to the V10. It would keep pretty close to a lot of supercars. Though there's so much more to life than racing in a straight line. A properly tuned civic could beat anything.
That being said, yes the R8 will get you laid faster! It's a very big attention getter on the street. Pointing, smiling, honking, all kinds of attention every day you drive it. It's a joy on twisty roads, and the engine noise is wonderful.
And it has a normal warranty so you can actually drive the thing! All in all it's a great car, but let's not get started on the trunk space!
The M3 is an amazing vehicle as well. I love BMW's. They have great interiors, and are so nicely designed throughout.
Both are great cars.
If anyone is having a meet soon in LA, let me know!! I'll bring the R8 out.