I have a D100 ... currently. I'd like to update to either a D180 or 7" Skyview.
I presume you are just starting on the upgrade path and looking at options.
Cannot comment on the SV systems as not been there or done that. It is incompatible with the D100 though (other than any AP servos you may have), so it would be pretty well a complete replacement.
I do wonder why you would be considering a D180. By the look of the CTSW its a side by side 2 seater. Why not just go with a D120 in front of the passenger and DSAB (network) the 2 together? That way you could display a mix of EFIS and EMS data on either screen, kind of like 2 D180s.
I have the two.
Normally fly in the cruise with EFIS on D100 and EMS + Fuel status on the D120.
For takeoff D100 has 2/3 EFIS and 1/3 EMS: D120 has EMS + Fuel status.
If I have a pilot in the pax seat we can reverse the cruise config so they get all the flight data in front of them when they take the controls.
The extra screen real estate is also really useful if you are a fan of the HSI (beginning to go that way myself) as you can have the D100 displaying EFIS and HSI with the engine data on the D120.
Just kicking ideas about! The above screen configurations are just a small sample of what is possible - take a look at the latest D100 manuals.
Bear in mind that any features that are in the manuals that your D100 lacks can be (mostly) be added with a firmware update - simply obtain the cable and the suitable (free) download and get your slaptop out!
Hope that helps!