Pseudo, you're a man of contradictions. You want a low-risk, guarantee on your mortgage. But you're already planning to work extra years so you can buy a Ferrari? How will owning a car that's worth the same amount as your house make your retirement less risky?

B42 already explained the math pretty well.

But here's a missing part of your thought process: you're only considering the first 10 years of the math. Have you consider how the numbers fair 30 or 40 years from now? I think you came here in earnest, so I'll take the time to post this using your figures considering a 30 year time-frame.

**Scenario 1: Pay Off Mortgage Early** (367K, 3.5% interest, 30 year term)

Additional monthly payment: $1,629

*runs mortgage payoff calculator* (see bankrate.com)

*result: mortgage will be paid off in 11 years, 4 months*

So at the end of 11 years, 4 months, you will have:

Mortgage loan: $0

Additional Investments: $0

Now, presumably you will invest the additional monthly payment + your normal payment in the stock market:

Additional Investment: $3,277/month

*runs investment return calculator* (see bankrate.com)

After the remaining 19 years, you'll have $1,525,048

End result after 30 years:

Mortgage Loan: $0

Additional Investments: $1,525,048

**Scenario #2: Pay off Mortgage slowly**

Additional Investment: 1,629/month

*runs investment calculator*

After 30 years, you'll have $1,915,810

End result after 30 years:

Mortgage Loan: $0

Additional Investments: $1,915,810

**Difference between two scenarios: $390,762**

*****Note this is with conservative, 7% investment rate of return. If you use 10% return rate instead of 7%, the difference is $1,268,003*****