Slow, clunky action = poor springs?

I realized today, in attempting and failing miserably to perform a specific gliss on my Zephyr, that it has the slowest, heaviest, clunkiest action I've ever seen. Don't get me wrong, I don't love it any less because of this, but I'd rather like to find out what the problem is and how to improve it.

Since I still have that old Cigar Cutter sitting around, which has the smoothest, most fluid action I've ever seen, I compared the two together. Now, I think that the King's keys have a greater degree of motion - based on the way they're designed, but I figured that wasn't the whole problem. So then I compared the springs - which I know very little about.

The Cigar Cutter seems to have those blue steel springs that everyone talks about. They're pretty small, and seem to bend very easily while still being quite durable. On the other hand, my Zephyr has these awfully thick brown ones (look like tree trunks in comparison :shock: )...it takes a lot of effort to bend them, but they are strong.

So - what's my problem? Do I just need to oil the old beast, or is it time to upgrade the springs? Are they causing the slow and heavy action?

If the latter is the case, please suggest what to upgrade to, and, if you know, also quote a full replacement. Thanks a billion! I look forward to playing Flight of the Bumblebee in the near future!