Compatibility issues with upgrading a 1991 1400a Miyata Road Bike I've only just started getting into bikes recently, so i'll try and be as accurate and succinct as possible. Apologies in advance if I confuse anyone.

I want to upgrade the wheels and crankset on my above mentioned Miyata with the hope that it will turn it into a leaner, meaner riding machine. I love the bikes aesthetic and frame quality, so i'm willing to spend money upgrading components. (Providing they will make an obvious improvement to its motion) 

However, it's current configuration is 700cc Wolber rims, 7 speed Shimano 105 hyperglide cassette, 105 front and rear derailleur, 105 7 speed downtube indexed shifters and a double Sugino VP crankset. I was wanting to upgrade to Fulcrum 5's/Mavic Ksyrium Equipe wheels, with Shimano freehub (or something in similar quality) and a modern 105 (or ultegra, money permitting) crankset. I really would like to keep my cassette and derailleurs as they are, if possible. 

So, (using Sheldon Browns 6-11speed article as reference) would I be able to install the wheels on a 7 speed cassette with a 4.5mm spacer without any problems? 
Would I also be able to use a 9 speed chain ring (as 7 speed 105 chainrings defeats the purpose of the upgrade, AND they are hard to find) with a 7 speed chain without any shifting problems? 

Also, if there is anything I've not considered or if any of you have a better idea of going about this, please tell me. I'm all ears. I just want to make the bike faster. 

Thanks!
Jack
The Miyata 1400a is made of aluminum. A  7 speed Shimano 105 system uses a rear spacing of 126 mm, which is smaller than the 130 mm needed for a modern 8-10 speed system. For a steel frame, its no problem to stretching the frame and get the wheel in. On an aluminum frame, you really shouldn't. 

That being said, people have done this at their own risk, by either fidgeting with lock nuts or spacers or whatever. I wouldn't recommend it though. 

The reasonable thing to do is keep the bike as is, maybe with a different cassette if you need different gearing. You can use the 9 speed chainrings in a 7 speed drivetrain. You can also put 7 speed brifters if you want to feel more modern (you'll end up shifting more often).