Cars networked electronics represent very complex systems. Ruling this complexity is a great challenge to future cars system designers. As there are no analytic solutions to the problem only good modelling in conjunction with trial and error methods will be apropriate to attack the problem. In order to produce results in a timely and cost effective manner a new generation of System Design Tools is needed to support the system design process.In the following paper a new method for assessing the system design problems is proposed: VLSA - Virtual Leveled System Architecture. A set of Network Development Tools - Simulator, Emulator, Analyzer, etc. - is discussed as the basis for efficient system design support.