Sorry rover416...but you've been some wrong infromation. Your 4kus 40x12x48 CDRW is a LiteOn drive.
Evidence...
1) goto _http://www.4kus.com.tw/products.htm and check out the 32x and 40x pics. These images show the faceplate and an exact match of any LiteOn OEM drive.
2) check out the 4kus drive specs...SMART-BURN® technology, SMART-X technology®, Easy-Tray® Design, VAS® Vibration Absorber System Mechanism. These are all LiteOn tech NOT used by Plextor. All the other specs drive acess time, etc also match LiteOn 40x.
3) The Plextor 40x drive (PX-W4012TA) has a buffer memory size of 4MB, while the 4kus 40x drive has a buffer memory size of 2mb...as does the LiteOn 40x.
Now I'm making a logical deduction here, but I'm pretty sure the 4kus 40x drive model # is CDR-5W40 and must equivalent to a LiteOn 40x LTR-40125W.
So to answer mic1's question...you should be able to flash this 4kus drive to a LiteOn firmware. However if you were to do this, you should learn to flash firmwares in DOS with Mtkflash v1.48 before any attempt to flash to a LiteOn firmware. For more information and tutorials, goto the LiteOn section of club cdfreaks.com (_http://club.cdfreaks.com).
However, if you have no problems with your media, there is no reason to flash the drive. Flashing can be dangerous and can lead to drive failure. Always be carefull when flashing...take your time and follow the instuctions carefully. Do that and you should be fine.