The TSD is actually the a re-branded Well. The parts are basically interchangeable with the UTG 96.
I have tested 2 UTG 96's, 5 TSD (WELL) 96's, and one WELL 96 with the adjustable stock. All owned by myself or my brother at one time or another. The UTG's seem to be just a touch better made than the WELL, but the TSD/WELL's are still fine. One of the first things I do with a new gun is corono it with a MadBull crono and record the results. One thing I noticed about the stock 96's from both WELL and UTG is you could range from 430-485 FPS, out of the box, depending on the "luck of the draw".
There isn't much to the internals to these guns and currently Atlanta Airsoft is the only source we've found to get the majority of the internal upgrades. Fully upgrading your L96 is an expensive endeavor when you compare it to the original cost of the gun, but then again, the same stands with the mid-range AEG's!
*** IMPORTANT NOTE - DO NOT mess up your stock air-seal/hop-up bucking!!!! The AEG air-seal/hop-up bucking WILL NOT work in your stock gun! We have yet to find ANYWHERE that carries replacement air-seals for the stock gun! Trust me on this, we have checked all the normal and not so normal places, and have spoken with quite a few store gun techs in our search. If anyone knows of a place PLEASE let me know! We have also tested AEG air-seals in these guns and they may work for a few shots then they tear up!
We have put DBC 6.01 (499mm) barrels in 3 of the guns. The increase in FPS was negligent and the accuracy increase was marginal but worth the accuracy increase it in our opinions. These barrels are cut specifically for certain sniper rifles and will not work in AEG's. That, of course, means that AEG tightbores WILL NOT work with this guns stock hop-up chamber! When your ready for a tightbore, purchase the aftermarket AERO hop-up chamber (Atlanta Airsoft), and an AEG tightbore barrel. (I'm in the process of checking to see if the DBC sniper barrel will work in the new AERO Chamber but it's unlikely. I will update later on this.)
We are also big fans of the barrel spacers that are slid onto your inner barrel to help support it within the outer barrel and keep the barrel from wobbling. Out of the box they only put 2 or three lame foam disks on the barrels to keep them in place.
The silencer adapter that's available also works fine. As with other guns, the orange tip in the TSD/WELL is glued in so heat up some hot water and soak the end for a few minutes to soften up the glue before trying to take it off.
Spector (my son) runs with a TSD L96 shooting at 475-480 FPS. Only added a 6.01 tightbore and barrel spacers.
Joker (my brother) runs with a TSD L96 with the internals being almost entirely aftermarket shooting about 540-550 FPS (150 spring) Will be installing the AERO hop-up chamber this week on his gun.
I (Chief) have a UTG L96 that I have had for more than a year with a tightbore and barrel spacers shooting about 460-470 FPS.
If you have further questions on the other internals we can answer them as they come up and as we learn.
We are by no means "experts" on the L96's! Just sharing our experiences.
All that said... if your happy with your stock guns performance regarding FPS and accuracy, then hit the field! And take 'em out! "One shot one kill!"