40125S with Memorex 40x CDRs

ok im confused about some stuff. hope you guys can understand me and answer my questions.

  1. When burning with Nero, should that burning process window say Smart-Burn activated? i check the setting it say it is enabled, but i saw some screenies that shows Smart Burn is activated?
    The only reason im asking is that i didnt reinstall Nero when i installed the burner so it could be that.

  2. (no warez here)If you were burning like for an example, WinXP with SP1 ingrated, and it had like 2 courruped files, could that affect how the buring goes? I burnt 3 cds with 40x with 40X memorex cdrs, it shows .14% unreadable and .14% bad in CD Speed Scandisc, but when i burnt another game or something with 32x dics and than memorex 40x, it was 100% perfectly with no errors, but it was just a 300mb file, so i was wondering if it possible that the lead out is courrupting the files? cuz most of the damged errors came at the end but also where the courrupted files are. Tonight i will make my own copy of slipstremed SP1 and see wha happens, but im wondering if courrupt files can interfert with the burning.

  3. i was wondering if anybody got any problems with 40x memorex cdrs and also is it always a good idea to burn at 40x? should i bring it down to 32x? but that would be like disprove the purpose of 40x burner and 40x.

  4. does it matter wha i used for the writing mode? Track at once or Disc at once. which one is better?

here my sys info

Windows XP Pro
Athlon XP 1600+
512mb PC2100
80GBWD SE/30GB Maxtor
and Liteon 40125S flashed to the latest firmware, ZS0N.