02 Honda Pport w/ 160K miles $4000?

Any engine can conceivably get you to 300k miles if you are the original owner who kept up with the maint. from day one. Sounds like your friend did not keep up with recommended maint at all. Take the car to a reputable mechanic for a thorough examination before you hand over $4k to your "friend". From what you say, the car has engine and power transfer issues, it may cost you another $2-3k short term. Spend the $150 and get the car checked out.