They are options. On MY05 500 it goes like this (this is copied directly from MBUSA's options page for the ML500:

2005 Packages
317 Comfort Package

Interior features include three-position memory system for each front seat and exterior mirror memory stored with driver seat settings.

Exterior features include power fold-in for outside mirrors and rain-sensing intermittent front wipers with a sensor that adjusts the windshield wiper delay for you.

324 Sunroof Package

The optional Sunroof Package includes a power tilt/sliding tinted glass sunroof and power rear-quarter vent windows with dash-mounted remote controls.

The heated seat is standard in the 500. Go to MBUSA.com and configure one to see al the options and accessories.