I can certainly vouch for the patience of RibCraft when it comes to boat set up. I think I changed my spec about 600 times! If it’s your first boat look for a manufacturer that will take the time to show you around a load of their boats, and do a sea trial. This will be the only way for you to work out what you want.
Regarding tow cars….. I’d seriously consider spending some of that 25k to change your car if you plan on buying anything over 5.5m Yes, you can tow a 6m boat with a Golf, but you might not want to learn to tow a 6m boat with a Golf
Most of the beginner Ribbing pitfalls revolve around launch and recovery. A little 4WD, (Subaru impreza/forester, Skoda octavia, Honda CRV) would give you a bit more leeway when you get it wrong the first time.