Wow..
More proof that an internet connection and keyboard = 'Internet Expert Commando'. And a bitchy one at that
Please explain how in your world a 'wider track' 'allows the use of wider tires'.
In the real world, wider wheels, and depending on their width, wider fenders is all that's needed.
Taking it a step further, you can run the widest wheels with the 'widest track' in the world, and it won't do a damn thing for you if you aren't running the right amount of negative camber. You'll simply roll up on the sidewalls of your $$$ tires, and be slower than you were with stock tires.
To address the OP's question about 135 being able to out handle a 1M with suspension work....OF COURSE IT WILL. Every single mass-produced, street legal car is built with compromises. Even BMW's M's.. If BMW made the 1M with track speed the only goal, it would ride like wood, and chew up tires in less than a 1000 miles. Since most people who buy these things not only drive primarily on the street, but NEVER even see the track, very very few would sell. The car rags ripping them up one side and down the other for having ZERO street manners wouldn't help either....neither would the multiple law suits from people who lost control of 'em while driving over a pot hole, and running into a light pole.
Contrary to this, what YOU do to your car is only limited by how much you want to move towards track orientation and away from street comfort. Moton/Ohlins etc.. produce light-years better shocks than the stock 1M's units, and the aftermarket is full of suspension pieces for the 1 series that when properly mounted, will leave ANY stock 'M' in the weeds, when properly set up. The down side to this is if you plan on driving your car on the street you'd need a kidney belt, and a set of the hardest compound tires you can find, as the only part of the tires that will be touching the ground in 'normal' use would be the extreme inside edge.
Upside is, when you get the thing on the track, you'll need a flak jacket to protect your ribs, as the thing will corner like a go kart.
I've personally gone this route before, as luckily for me at the time the car was not my primary, and I had a trailer to haul it back and forth to the track.
The REAL question is, how much modification/improvement can you do to a 1-series' suspension, yet still retain decent street ride quality and tire life.
If you only drive your car on weekends, equating to only a couple hundred miles a month, then you'll probably be willing to deal with a stiffer ride and shorter tire life on the street in order to gain quicker lap times and longer tire life on the track.
Point being, the answer to the aforementioned question is going to be different for each individual car owner.
