Gracjan
You can return the drive even if you install it and take it around the block a couple of times. in past CD-RW deals from OM, people have return drive after they use they without any problem, and I have never heard someone say that OM wouldn't take back the drive because it had been opened.
Also I think that it a bad drive, it just that there's almost no infomation on what kind of performamce you can expect from a BTC mfg drive.
officeMax's Return Policy (from their web site)
If you are not satisfied with your OfficeMax.com purchase, simply return it to us in the complete and original packaging (together with all accessories and manuals) with your original sales receipt within 30 days of the date of purchase. We will gladly replace or repair the item, or return your money. Electronics, digital cameras and business machines must be returned within 14 days of purchase. OfficeMax.com will not accept returns of opened digital cameras or software packages unless defective. Software and digital cameras that are defective may be exchanged for identical items only.
Products that are purchased on OfficeMax.com may be returned to an OfficeMax store location for a credit refund. Product returns may be exchanged if the originally purchased product is in stock at the store location.