Agree with FD. I would just add that 15hrs is pretty optimistic; 25hrs is nearer the mark to be able to pick up more or less any approach plate and be able to fly it.
Also you don't say how many hours you do a year. If less than 20-30, the IMC Rating training is just going to get wasted - unless you just use it for en-route (e.g. VMC on top) but then you have still got to pass the flight test regularly...