If i woud have 2 diffrent internet conections from 2 diffrent ISP (using 2 NIC's), woud my download speed be faster then if i woud only be using 1 conection from 1 isp?
No. You can only have one broadband/dial-up connection on one phone line, and even if you have wireless I doubt this could be done, and even if it could it would be massively impractical and expensive, IMO.