As far as I know the TLA# is the production run batch code.The changes may not be very big or may have no change at all.My personal opinion is that too much is placed on the TLA# of a Plextor.It seems the more I read about SD2 the more it become clear that there is a lot of misinformation around and the fact that SD2 has more than one version isn't helping.The fact that programmers can also program the type of SD2 with different options is lost on some people and from what I have read that some burners can copy some SD2 games and fail on others seems to confirm this.This is just my take on it all from reading forum posts and reports on a lot of web sites.Please feel free to correct me if I'm wrong in any area.
The jumpers you mention are the factory reserved ones and reports have said that jumping them will put thr drive in to UDMA33 mode.
This is what http://www.justcdr.cjb.net/ reports.
"If you facing problems when try to read SubChannel Data with your Plextor based recorder there might be a solution for you. All the above drives have 2 jumpers next to the digital audio out. If you jumper them then you drive would recognized as UDMA33 and probably it will start reading SubChannel data. We tried it in our TDK CyClone 121032, which refused previously to read SubChannel data, and worked fine with latest CloneCD (126.96.36.199).
This is the official Plextor answer about jumper the drive:
"...The "Reserved jumper" (2 horizontal pins next to the digital audio out) is used for testing during production. If these jumper pins are shortened, some PC motherboard will work at Ultra DMA-33. But we do not guarantee the working..."
All I can say is get on the net and read up on it all and do a bit of your own homework.The info is out there you just have to look