As Stan said, these cars aren't for everyone. A 993 Cabrio will likely be faster, handle better, be more comfortable, and go largely unnoticed in a parking lot. A Speedster or Roadster will look like a classic, require some sacrifices in comfort and refinement (like the originals, but not as much), and generate a conversation with strangers wherever you go. Part of the reason we love these cars is precisely because they are relatively crude and you are close to the machinery. You find yourself looking for excuses to drive anywhere - or driving nowhere in particular - simply because the simplicity and, yes, crudeness, takes you back to when travel had an element of adventure.
I love my Beck, and strongly recommend it as the best mid-priced value - but I am hardly impartial. Henry's cars (IMs) are considerably pricier, but also have a measure of sophistication above the others. Beck doesn't yet (but will, for the patient) have a model with roll-up windows, and, by your questions, I would think that would be a benefit of an IM that you might want. If I'm wrong, contact Carey Hines and spec out a new Beck for that price.
As a daily driver, the 993 is probably a better choice. The very things that make it a better choice for daily use make it a poorer one for an adult toy. For pure, unadulterated fun, I know which one I'd choose.
PS - Yes, the 993 will be faster than a 1776cc IM, but the sensation might be less entertaining. Are you after outright speed, or outright fun?
PPS - The 993 is a great car - the Speedster/Roadster is a hobby. Dusty is right. If you're after a hobby, it's hard to beat this one. Ok, I'll shut up now.