Got an LTR48246S which will write at x2 ,I almost never go that slow usually x16 + never had problems.
You could upgrade the firmware (wont do no harm), Always keep mine up to date, The last Firmware update i got was only to improve overburn capability.
How is the LTR52246S ? I didnt fancy that one , does it actually write at x52 ? I couldnt find a blank cd that supports it !!