X100 Weird Prices

So, looking to purchase a second Jag, idea is (never works out this way) to buy with a view to use occasionally during summer days and probably lock away for the rest of the time (although struggling to find storage at the moment), with a view if I get a good XK8/R, prices will go up over time and I have myself a very nice convertible for the occasional nice sunny days in the UK.

Only just started the search, but few thing have struck me, prices seem to be completely random, now not physically been to see any yet, but from pictures, descriptions. mileage, owners, even colours, prices range significantly, more significantly than I have ever seen on any other car at least which is weird. Maybe just current climate, but feels like if you know what you are buying, maybe some bargains to be had?

Anyway, key question, what colours, specs, limited editions are worth keeping any eye out for, what is a realistic good price, heard a few times these cars can suffer from a little bit of rust etc and the older ones have had a few engine issues. 

Any tips would be great as I start my search for a good one, luckily no short of cars out there.