Best way to present a LOW ball offer!!

[Rick Edgeworth]

Situation: Seller still in house. Been on market for 10 months. Info from realtor is no offers have been made. Original list 619,000 and still listed at that. Looking to move my family in as we just sold our place. Needs about 75k to get where I want it. Based on market and perceived not so great financial position of seller I'm thinking to offer 450. Should I write a letter complimenting the house yet explaining it would need significant mods to get where we want it or just let realtor shoot it over!? Your thoughts please!!