Most of the cons are just some of these hyped up rumors that comes part and parcel with the internet.

Gran turismo is part to blame too as alot of people took the bit about loosing torque and slowing down going up hills too seriously.



Pros, makes the car far faster to accelerate especially if its being put into a car that previously had a dualmass flywheel.
In some cars, the difference in weight is nearly halved and also the enertia of the old flywheel can be higher as well even weight aside as alot of the mass is at the outer edge.

For example on some cars, putting on in can make 4th gear feel as quick to pull as 3rd previously did.

Rev matching is nicer, heel and toe can be done alot quicker


I find driving around town is actually easier really and the car doesn't seem as lazy. This poor idling and difficult take offs is only if you go very light altogether and use a fancy clutch or coupled with very aggressive cams with wide overlap.



This thing about loosing torque is total bullshit. A flywheel doesn't make or loose power so you can't lose torque.

If reduces the rotating mass and inertia of the drivetrain alright therefor it can be easier to lose momentum but thats only relevent in something like a tractor or truck where your flying along the flat at 2000rpm and then hit a hill and start dropping back to 1500 or so.

In a car, if your flying along at 60-70mph at 2-4000rpm, you'll have another 4-6000 in reserve and plenty of throttle to open.

And as the engine is more free to rev, it'll only have the hill to overcome rather than the hill and a heavy drive-train to accelerate.



On some flywheels, skimming them on a lathe is fine. I know plenty of race cars that have had no problems once the flywheel is setup properly and true on the lathe and I have fitted quite a few lightened flywheels to road cars and no complaints so far.

Obviously on some, the balancing holes get machined off to lighten them so your going to run into problems then alright unless its properly balanced afterwards.