Block or Inline Heater?

[neckland]

I live in Calgary and purchased a '90 525i in June 2006. This winter I have learned that the car hates the cold weather. It's a Japanese manufactured car and has no block heater, which are standard options in vehicles up here.

I am now in a position where I need to either install a block heater or some have suggested an 'inline' heater.

Could someone tell me their thoughts on these two different options? Also the level of difficulty to have this done as well as the estimated costs?

Any and all suggestions and comments would be greatly appreciated.