I'll give it a shot ChickenMan.
The aspi layers is due mainly for WinXP users (& a few win2K).
WinXP doesn't come with aspi support, only roxio crapwear. So if you try installing most burning software, it won't work. Usually gives you some error about not being able to find aspi layers.
Some software (the newer ones) don't need them anymore, well I should say they need them, but actually already installs them for you if your system doesn't have them (eg: Nero, CDRwin, CloneCD).
That's the only real fuss about them.
On the other hand, I have a friend on win2K that doesn't seem to have aspi layers installed into it either, so he also had to install them.
Most people use this one (which is actually a layer taken from win9X & winNT systems):
h**p://xp.xyu.ca/drivers.htm which is the good one to use. Adaptec have just recently released some newer ones, but most who have been using them find it to be junk. Probs another way for them to keep their software/hardware looking better (I don't really know).
Anyhow, there is no need to install ASPI layers, unless your software doesn't work, so if your system is working, leave as is =)