Just the Eaton alone? Maybe $450 if its mint and hasnt been pullied...they seem to be going for less and less nowadays...Ive seen some go for as low as $300.
If you sold the whole system... Eaton, Intercooler, Lower Intake, HX, etc you could probably snag $1500, or even trade with a Mach 1/99-01 for their shit plus cash.