I know that MSAR is gone, but I didn't think the trigger modifications/upgrades would dry up so fast... the TSM is out of stock, the K&M piece has been discontinued (for reasons beyond MSAR's closing), and it appears the only "big name" game in town is the Neu Trigger.  Should I fo? Would you recommend it?

I got a Neutrigger around a month before MSAR went belly-up,and I'm glad I did.Makes the trigger smooth and reduces trigger pull at the same time.I like my E4 even more now,and will never part with it.

Neu Trigger still makes it.

http://www.neu-trigger.com/


They Steyr and MSAR use the same one.


http://www.gunbroker.com/Auction/ViewItem.aspx?Item=486056454

The TSM is out of stock because it is better than the rest. You could wait for more or buy an alternative.

http://www.kmaerospace.com/MSAR.shtml

I have one of the coveted pre-20/20 MSAR trigger packs from Ratworx.  
The trigger module itself is interchangeable between the MSAR and AUG trigger housing, and works equally well in both.
I also have a MSAR pack with a Neu-trigger band installed.  It also works very well, and is a huge improvement for the money.
When I had both installed in two guns, some people who shot them actually preferred the Neu-trigger.  They liked the slight but smooth Glock-like "roll-off" effect.  
While the 20/20 is fully adjustable to a superb match grade pull, If I didn't have both, I would still remain very satisfied with just the Neu-trigger.