JR,
In situations like this, you always have to look at the worst case scenario. If an unexpected expense is going to break you, do not do it.
Nothing is worse that living beyond your means, I wouldn't be able to sleep at night worrying when the next ball might drop (that's just me).
I know how tempting this must be so look at your budget real close and think of what you would do if fuel costs were to go back to $4.50+ per gallon. Everything on 2003 coach is 14 yrs. old and may last 20 yrs. but it may not. So, budget accordingly.
Good luck!
MM.