EBay recommends that prospective buyers of crate engines consider the wide assortment of options available from resellers and that any crate engine purchased include all kits and parts necessary to install the engine properly. It also recommends ensuring the engine is specifically designed for marine environments if it is to be installed in a boat.
EBay encourages buyers to learn all they can about an item by reading the complete description and asking the seller any questions they may have before buying or bidding on an item. EBay recommends that its users buy from reliable sellers who have earned good feedback based on previous sales, including a review of the feedback that a seller has left for others.
EBay advises prospective buyers to look at completed listings of the same or similar items in order to gauge the fair value of an item they're considering and to then decide in advance how much they are willing to pay for an item before placing a bid. EBay's extensive Help section provides additional tips on all aspects of the buying process.
The blog at eBay Motors contains anecdotes about people who have used Crate engines. These anecdotes are easily found by searching for "crate" within the Motors section on eBay.