How many days of cross training should I do a week?

I have been doing the following:
1. Fitness runs on Monday, Tuesday, Thursday, and Friday. (40-60 minutes comfortable)
2. Strength run on Wednesday. (10-15 minute tempo w/ one mile warm up and cool down)
3. Endurance run on Sunday. (60-90 minutes comfortable)
4. What I call cross training on Saturday (bike or swim for 30 minutes)

Should I be doing more cross training or different kinds of cross training? What has helped to run your fastest times once you got onto the track in the spring? I run the 800m, 1500m, and 3000m, not in any particular order.

What is the difference between the Nike Lunar running shoes?

I need new running shoes and I heard the nike lunars were good but I see 4 different kinds.

-LunarElite
-LunarGlide
-LunaRacer
-LunarSwift

What is the difference between these 4? And I am using them for distance running like for cross country