It's amazing how many different views there are on this. My gut feeling is that I want to enjoy my mini rather than worry about it, however that said I know how it feels when a mini goes from 'perfect' to rust bucket!
I ran a mini for 10 years in all conditions, and in Scotland we get ALOT of salt on the roads. I was quite naive about minis and how they rust back then, and I thought that as long as I washed the exterior it would be fine. I did not treat the car underneath in any way, nor did I get up under the wings, arches etc and clean off dirt and salt, maybe a quick squirt under there with the hose now and then. The car went from as new condition to really quite rusty (bad enough to be off the road for alot of welding - still is) in the 10 years. But like I say that was daily use, alot of miles, no protection and no proper cleaning of the underside.
My current mini is in as good if not better condition starting out, and I have spent some time getting all under the wings, arches etc treated with clear dynax wax, and the box sections treated with dynax cavity wax. My plan for this mini is to try to avoid using it much in the winter months when salt is on the roads, and to be more diligent cleaning it.
I had it out last weekend in the rain so it got covered in salt. I spent about 2 hours cleaning it - wheels off and under there for some careful cleaning with soapy water and a rag, and rinse off with a hose. This is how I plan to proceed - minimise exposure to salt, and regular thorough cleaning.
I think getting a good quality wax onto the vulnerable areas of the car (pretty much the entire underside) and regular cleaning is essential, and if done should make a big difference. The way I see it if I can get 10 years without doing anything right, then by doing the above I should get alot longer, or at least the amount of rust which gets to take hold should be less severe.
I certainly wouldn't let lack of a garage put you off. Get your mini, get the best one you can bodywork wise (if you can get a jap import I highly recommend it - that's what I have bought), sort any obvious rust that you can, good quality wax underneat (clear is good as you can still see what is going on - the Dynax stuff is excellent), and then enjoy it.
Edited by carlukemini, 05 March 2015 - 05:28 PM.