Yes, if you want to overclock you have several possibilities. You can flash to a LiteOn 48125W using Mtkflash and firmware VS08. I’ve done this with my Memorex 48MAXX 1248AJ (same drive as yours, with different firmware). Or if you want, you can flash to Memorex 48MAXX 1248AJ if you’re hung up on the Memorex name. I’d recommend you just turn it into a LiteOn using VS08. Everything you need to know is in these threads:
Make sure to back up your current firmware so you can flash it back to its original state, if need be. Read the Mtkflash guide, and get an understanding for how it works before using it. Using it to back up your current firmware is good practice.
Oh, you can get the VS08 bin here:
Overclocking your drive invalidates the implied warranty.