When paying estimated taxes, 4Q98 due Jan 15, 1999, will there be any penalties associated with a large over payment? This question is due in part to unresolved issues surrounding my converted Roth IRA's. I'd rather pay them more than less just to cover my options. Thanks.

I assume that you mean by overpayment that you will have a refund when you file your tax return. If this is the case, there is no penalty (other than the interest that you lost by giving the government money that didn't belong to it) for the "overpayment."