I am an expat myself currently.
Things you need to watch out for:

Home country where u currently are-
when u sell car to relocate, do u make a loss? does company compensate you?
does company help you do all paperwork related to getting u to the new place?
after u sell car, does company provide u with rental car until u r relocated overseas ?

Package-
car allowance there? or company car?
housing?
air tickets/budget in cash for home visits?
if u have family, kid;s education? wife's loss of income- is that compensated ?
health insurance - does company cover u 100% for medical overseas?
general allowance- % of base salary
salary structure and bonus structure...make sure you are not short changed on what happens in home country versus your new host country as you are an expat now
taxes - how does company help you offset EU taxes and how is your salary affected by this ?

Upon repatriation to home country-
When u sell car, any compensation for loss?
rental car and hotel stay during the transition period ?