The offsets on the E430 is ET35-38, and these are ET19/ET20 so in theory they should fit, people have done it but you would need to check, if they did any arch rolling, but in my opinion they would work as i have just a done quick google search and there are several people running 10x18 with same offsets on OZ wheels.
As far as delivery is concerned, like i said previously, i do send several sets of wheels to USA to forum members and the price is around the $300 mark, at the end of the day if i quote this figure and somebody pays me this figure then you will get the wheels, if the rate goes up more any reason, then you still pay this figure, it would be my responsibility to get the wheels to you for the agree price, i always use FedEx for my international deliveries.
as far as the authenticity of the wheels, in the earlier models, the OZ was stamped on the middle of the wheel near the lugs as pictures below show and these are the pictures of the actual wheel for sale not google images, thanks