In reply to moneykat:
The problem with buying a pair of boots for markedly different things is that you often end up with boots that do not do anything well!
If you buy a pair of alpine boots and use an overgaiter, then you still need the boots to be a bit larger than normal to allow extra wiggle room. This may limit their suitability for more difficult alpine climbing. On the other hand a pair of double plastics will be fine for IP but I would not care to use them for anything other than easy, or perhaps winter, alpine stuff.
I agree with Radson that IP can be pretty hot. The normal route stays on the eastern slopes and then the ridge to the top. I have also done IP twice. On the normal route I used Evos and overgaiters. On the North Ridge I used Asolo 8000s. Both worked for me.
If you are unlikely to return to 5000m+ peaks, then perhaps renting plastics in KTM might be the best option. Talk to your trekking company about sizes. Renting also means that you do not make a loss on plastics that you cannot use because you have altitude problems.