F1 bigger tires, longer wheelbase.
Adds up to better handling.
No the chassis's aren't interchangeable. In fact, it is even more complicated than 3 chasis's. There are at least two MR01 configurations...I think the second might be referred to as a MR01.5. Then there are a couple MR02 configurations. There is the Overland series which has a longer travel suspension...with the front and rear suspension being similar. And finally, there is the little monster truck models....there are two of those...only difference being color schemes.
The MR01, MR02 and F1 all use pan-style, flex leaf rear suspensions (called "H" suspensions) also seen on the Micro RS4. The Overland and Monster have similar suspensions (pin and spring) front and rear. All are two wheel drive (some competitors, like the Mini-X's produce 4 wheel drive models.)
In stock form they run about 19kph. The iWavers run slower stock...about 12kph. Hopped up motors run closer to 24kph. There are even faster motors but you'd be looking at a FET upgrade.
We get a lot of spinouts and burnouts with the stock tires. With soft rubber tires or foams, they stick much better but the MR01's traction roll fairly easy if you aren't careful (even the MR02's will traction roll if pushed real hard with sticky rubber.)
The things are a blast to race on RCP tracks. You really don't need any more speed than 19kph (the stock 12kph iWavers can be run flat out around the track.) I'm redesigning the RCP track walls. On RCP tracks, if you hit a wall, or even nudge it, you come to a complete stop...very, very annoying.
You can race more cars on more channels, by purchasing the Xmod, frequency crystal upgrade set (which are completely compatible.) That adds 6 more channels to race on.
A stock MR01 or MR02 body is in serious danger of losing the mirrors...and if driven off an RCP track will most likely end up with a chip here or there from hitting less forgiving surfaces, like chair legs. Some bodies have more robust mirror designs...like the little Subaru and Mitibishi Rally cars and the little Audi TT. I've not seen a raced Porsche that still had it's mirrors. The F1's, mostly because they don't roll so much, seem more robust. Replacement bodies are available and you will soon have "racing" and "modeling" bodies for your cars.
Mini-Z's bring racing home. You can set up a permanent or temporary track in your basement or on your patio. You will end up racing more often. Great fun.