yea, I've asked a lot of the same questions...I am just about to trade the DAX and EuroBUND...and...my only concerns have been the trading using the Euro from a USA account...like you, I live in the USA...my concerns have been:
1- how is P&L recorded
2-how it total p&l recorded
3-conversion rates
4-getting a BAD exchange rate etc.
5-cross trading US and Eurex products in the same day and the p&l getting messed up
..can anyone help