Late to the party here.
For most things 2.5s are better than 2.0's. When your sprung mass starts to become equal to unsprung mass, 2.5's can be problematic to tune and get a decent ride quality.
Not impossible, but that setup sucks to tune either way.
The initial crack pressure of getting the 2.5 shim stack to move vs getting the 2.0 stack to move, before it knocks your teeth out in the seat.
2.5s typically have some features that make working on them easier than 2.0's. How the coil hardware comes on/off, how the misalignments go into the uniballs, and also generally have better pistons than 2.0's.
Adding resi's to emulsions is a night and day difference coupled with a decent tune.
It takes a big change in valving to get the DSC to function well. You can get them to work better, but it takes a lot of time on the compression stack on the piston before you start to feel noticeable differences in the seat with dsc's.
They can be beneficial but that's a lot to spend for what you get. Spend not much more and you could just about be into a coil carrier/bypass setup.
Internal bypass are neat, can be more difficult to tune than others, depending on which ones they are. I wouldn't spend money on them.
