steve, tim has not ever had to deal with amsoil and their warr. like others that have been on here, he'll find out later.
I would like to say that oils do not swell seals. also, if you change your oil, you wont have sludged. now if you want to clean your engine, then from what I have seen, alot of people use auto rx. it will stop certain leaks. they also state that it is best to use certain oils with this product.
no oil, and I mean no oil will trash and engine. if it is oil, it lubricates and that is what an engine needs. especially if it has the proper api seal that your engine calls for. now if you use an additive, you can trash that oil or additive with that oil. that in turn can hurt your engine, maybe.
seals can be cleaned. but once they have harden by the dirt around them they don't come back to life like they were before. take the valve steam seal, you can clean them but they can and do get hard after awhile of being under the dirt. you can get them to rejuve a little but better off replacing them. the auto rx will seal the leaks to some degree. the neutra does not. it will rejuve a little on the seals but thats all.
amsoil is a good oil, but you should know about oil and not just go off of claims put on by that oil company. mobil is good also but like some say, it wont do every thing it claims to do.
I use schaeffers as I found they offer the best td sheets that is offered and don't hide anything. since being in biz since the 1830's I would think they know what they are doing.
this is a pic of the cleanout I use.
http://img2.freeimagehosting.net/uploads/41943ca087.gif
here is the link if the pic doesn't work
http://img2.freeimagehosting.net/image.php?41943ca087.gif
that combo conditions seals as well as cleans.