if you are considering automatic mini , go for 2nd generation (square lights)....if you are ok with manual then both 1st gen and 2nd gen are equally fine..
- 1100cc is best engine, tough & rugged....(in some cases you need differential replacement with this engine to get lower rpm)
- 660cc turbo is good engine but requires care...
- simple 660 cc is under powered....(not recommended)
(while buying check turbo assy not leaking oil and engine not giving smoke on high rpm).
engine change in older models is a normal thing.....
get radiator serviced thoroughly and replace coolant ... if radiator is worn out replace it...install electric fan if problem persist ,(pic given in above post).. there will be no issue of heating.....