Factory infintiy amp vs. aftermarket headunit

I have a sony headunit in my truck now, running through the factory infinity amp. I can run my own wiring to the speakers, which would be better? Off the amp or the headunit?

what year xj do you have.....
it has a stock infinity amp?
I would say that depends on what the amp output is vs the stereo.
Infinity , in my experience, has better audio processing circuits than Sony.Once it enters the amp, the signal gets broken down and re-processed ...
I am not a fan of Sony head units or stereos.

Keep the amp. I'm running an Alpine through mine, and it's noticeably improved over the last XJ which had the same setup only minus the amp.

Decent speakers will help more than bypassing the amp - my 2000 with the Infinity package has the Infinity amp, but came with some truly craptastic (though Infinity-branded) paper speakers that were nowhere as good as the Walmart-special $35/pair Pioneers that replaced them.

I'll second staying away from Sony. I used to be a huge fan of theirs, but somewhere around the 2000 timeframe their quality went right down the toilet.

I'm running a Sony head unit but the damn thing always beeps when you turn the ignition off "warning you to remove the faceplate for anti-theft".....

That's annoying but otherwise I don't have a problem with Sony.

The Infinity amp is quite a thumper when it comes down to it. My ex's ZJ with a Pioneer head unit, factory Infinity amp, Kenwood speakers, 250w RMS Kenwood amp bridged into 4-ohms, and a set of DB 12's in a sealed box (basically about $500 in it all together) sounded a lot better than mine witch consists of a Pioneer head unit, Alpine fronts, Claron rears, Kicker ZR360 amp bridged into 2-ohms, and a set of Kicker Solobaric subs in a sealed box (probably about $1800 in mine all together) until I added an amp for the mids, and highs.
Even with the amp I still think hers sounds better at a normal listening volume. Now when you crank them way up I definitely have advantage with the higher wattage components. Also IIRC the Infinity amp is somewhere in the neighborhood of 65/70w RMS a channel. More than your Sony head unit anyway.

OBVIOUSLY you guys werent blessed with tthe factory "Accusound by Jensen"

Of course they have been replaced over the years by Pioneers....

Its a 99, with pioneer speakers