Gear Vendors in 69 Dart

Having looked at all the current threads I could find, on FABO, regarding Gear Vendors in 67-69 Dart, I have questions. It seems some have had to cut floor up, while others have simply clearance tunnel with an air hammer and blunt bit. Can those with experience installing please give me the straight goods, can these be installed without major surgery?

My application is 69 Dart Swinger, A833 4 speed.

For those with experience, any notable issues with driveline vibration?

Would you install again?

I have both a 3.09 commando box, and a 2.66 box I could use, any preference? I have 3.23, 3.55, and 3.73 carriers I could choose from.

From those with experience, any input good or bad is appreciated.

If I've missed the answer in a previous thread, my apologies.