My recorder is a lite-on and it will burn at 8x. I usually burn at 4x because I thought I heard somewhere that burning much faster may create problems. Any opinions? thanks.

It's generally best to burn at the rated speed of the media.

As you've a Liteon you can perform disk quality scanning with either Kprobe or Nero CD/DVD Speed. Kprobe is specifically for Liteons but Nero maybe easier to interpret.

Burn a disk at 4x & 8x & compare the results.