When ever you are unsure always use the lower number
i386 and i686 have different processor optimizations. i386 are optimized for no processor.
i686 are optimized for Pent II and AMD k7 (durons/athlons).
Don't use the i386/i686 packs under a 64-bit processor, they won't work.
At any time you are unsure enough to post the question somewhere, just grab the source and compile it yourself. Often when you compile ANYTHING is will be faster and take up less hard drive space then a pre-compiled/package install.
Compiling = good
when you compile you can add in options that make the driver/software faster and more stable, and you can customize many of the defaults making the OS what you want it to be.
The only downfall to this is having to read the muanual that comes along with the driver and/or software to know which options you need st set, or which you can alter.
I hope you got some useable information for that gabble up there
