Pass Labs ALEPH 5 vs ALEPH 2

Isn't the Aleph 2 160w into 4 ohms? (Not quite doubling down)

You're patly right, that's what was shown in service manual but doubling down shown in my owner's manual. Based on its circuit, more likely 200w for 4 ohms. If fact Aleph amp is so good that I'm going to diy myself after the parts and enclosure arrives.
OTOH, rule number one, you need the speakers on the efficient side in order to appreciate how good Aleph is because its full-time class A and single-end/2-stage design.

Cdma, I heard a while back that getting a bigger power transformer was a help for the Aleph P pre (which I use to drive the 2 monos). Any truth to that, and if so, is it cost-effective? I don't really need to open a can of worms for myself or anybody else, however! Thanks.

Subaruguru,
I haven't pay too much attention to P in the past so have no idea about what you said. But I do remember seeing somewhere that Aleph amp prefers higher pre-amp output and a possible stepping attenuator upgrade for P. Also if I use bigger transformer, cap and heatsink, I might be able to increase the bias for better sound and higher current. Now I'm thinking about fine tuning my Aleph 2 and upgrading ARC LS-3b to P. What do you think about P comparing to the others ? a noticable upgrade from LS-3b? Thanks !

Yes, all the 2 stage Alephs need a high-output pre; the Aleph P essentially provides the third stage that was there in the original first Aleph, I think, along with a fine servo-driven stepped attenuator. It's an incredibly quiet, neutral preamp, and of course drives the Alephs seamlessly.
The remote is the best, too. Having separate gain and volume controls allows one a "balance" control as well the ability to dial in a bit of stage depth variability, although I simply follow nelson's advice and use the final attenuator set at upper scale, with gain pots semi-permanently set mid-scale, slightly unqual to offset assymmetry of room. Works great. Let's not hijack the thread....