THIS.
Everytime I think of dropping more than 20% of the value of my car on a mod, I generally just look at selling the car and upgrading. I mean realistically speaking, do you think Juliette is ever gonna see $90,000 from the sale of the car, even if it has that much in mods and maintenance? Makes it even cheaper when you realise half the people who mod cars are in debt and sometimes get strapped for cash, which means you can wrangle an even better deal.
Of course you don't buy if the car looks or feels molested, no matter what the seller says. Use your brain and not your dick when you buy a car. If I am buying a risky car I make sure the saving I make covers the cost of a possible fix... never had to be in that situation, but that's the mentality I approach it with.