Not unless you can prove that you were legally poorly advised. You can't appeal a sentence just because you don't like it, there has to be some factual basis to your appeal.
That would be a "no contest" plea. You're not admitting guilt but you realize the prosecution has enough evidence to convict you.Added: SUch a plea as described above would be a plea of Nolo...
You can try, and your reasoning is going to be that you were inadequately represented. The question is can you or you new attorney persuade the court of this allegation. Consult with a new attorney...
They are both a part of the same process. The defendant (or his attorney) offers something to the prosecutor in exchange for the prosecutors acceptance of a plea of guilty to a lesser offense, or a...