Is Advansys 5140 good enough for my burner?

I'm planning to buy either a Plextor R412 or a Yamaha 4416s burner.
I will also need a SCSI-card.
Will the Advansys 5140 be good enough?

I'd recommend you to go for Plextor. If it doesn't already comes with a SCSI card, then I'd suggest you buy one from Adaptec. They are very experienced in SCSI related controllers and is supported in Windows without any updated or special drivers.

The card is probably good enough. If you're not going to be doing anything else while the system is burning (as you shouldn't anyway), you're probably fine.