Since we have no control of the external market environment, how can we make purchase which is reasonable and matches our characteristics? First of all, you should know more about the environment like the factory head unit system of the modified vehicles and the electrical specifications of the vehicles, including the size of factory head unit, the size of its extension, quantity of speakers (amplifiers), power, layout, engines (battery), output power etc. In this way you can achieve the following purposes: 1. Have a thorough understanding of the performance. 2. You can give up the unpractical ideas. 3. Draft your own plan and know your own initial ideal product.

Second, make the purpose of the purchase of GPS DVD Navigation very clear. It is neither difficult nor easy to say that. Some people replace the factory head units in a hurry after just buying the new vehicles. This is not appropriate at all. You do not understand the performance of the factory head unit. Lacking the experience with the former one, then you don’t have made any comparison between the new one and the former one, which can easily lead to your sense of loss to the new DVD Navigation. Follow the viewpoints of the others blindly can go to another extreme. In this immature market, if you repeat what others say and follow what others have said, you will lose the initial idea and run into an indecisive dilemma. The correct approach is that we first find out the bad points or shortcomings of the factory head unit, such as no enough functions, sound of poor quality, improper matching with the original system and so on. Then finalize the several alternative plans, at this time you can listen to your friends and the experts. But do not hurry to come to decision. After that you should make comparisons between each plan in term of performance and price. Work out the reasonable budget according to your own financial situations.

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