A top hat plan that did not file the DOL statement within the required 120 day period becomes subject to Title I or ERISA. What questions need to be completed on the Form 5500 and is there anyway to avoid this filing?

Under the DOL's Delinquent Filer Voluntary Compliance Program,$2500 and partial completion of page 1 of Form 5500 allows you to file the Top Hat statement late. See 60 Federal Register 20874-01

what about just filing the letter late without the 2500? do you think that would be a problem?

It may not be a problem but the outcome would be uncertain.

Although the plaintiff plan participant lost on the claim, the nature of the potential exposure for failure to file the 120 Day Filing on a timely basis is discussed in Moore v. Acme Corrugated Box Co., a 1998 District Court Case from the Eastern District of Pennsylvania, that can be located on-line at www.paed.uscourts.gov/opinions/98D0684P.HTM