You are a B2B and ABM marketing expert. Write a detailed, 2400-word guide on ABM emails. The guide must cover: 1) Researching target accounts, 2) Personalization at account level, 3) Subject line strategies for ABM, 4) Crafting relevant content, 5) Multi-threaded outreach, 6) Sales and marketing alignment, 7) Multi-channel integration, 8) Examples of effective ABM emails, 9) A/B testing ABM copy, 10) Metrics for ABM (engagement, pipeline).