hey keithander,
i'll help with what i can. let me first say that i agree that the diff removal process is extremely painful with this car. as far as the steering goes...i've had the same problems as you. i'll assume that you do have, and run, a diff in the front.
i think the car was really meant/designed around running the front oneway. i've finally got the car to work on carpet by using double diff setup and opening the layshaft one way for off power turn in. it's not perfect, but it was extremely fun to drive that way. the front one way is so aggressive off and on power and i feel that without it, it the car doesn't steer well at all. trouble is, i can't get it to work with the front one way in. most of the others on this thread really love the car and don't stray too far from kit setup. i dunno the secret, but i wish i had it.
on carpet, it's almost impossible to not have enough steering. the trouble lies in getting steering AND maintaining high cornerspeeds. what i like about the diff is that you can always open up the layshaft if you need some off power rotation. you should post your setup and then we can comment on what it may be that is the main contributer to your poor cornering characteristics. where is the steering worst? entry, middle, or exit? on power, off power, or just at constant speed? these are often difficult to judge or recognize, but are great pieces of information as they will dictate what parameter to change on the car in order not to worsten other handling aspects.
the diff rings need to be ca'd to the outdrives during assembly. that should fix the slipping, and just a few tiny drops will do.
if you do give up on the atlas, the xxxs is a great handling car that's easy to dial in on any surface. but won't it be more fun when the atlas comes together?
later.