My soon to be 16 year old son wants a system for his 97 Toyota Avalon sedan. It has 144000 mi on it. My recommendation for him is: Kenwood Excelon KDC-X396 headunit $120, the front and back door speakers are 4 inch's so I'm thinking Alpine SPS-410 which hold 45 watts rms for $41 a piece. The 4 way class AB amp to power the Alpine 4" speakers well how bout the Rockford Fosgate Prime R300-4 which is 50 watts rms x 4 for $120. I'm going to put 600-800 htz bass blockers on the 4" speakers for $20. Due to 4" speakers aren't made to handle lower htz without blowing I've found out. The amp wire kit a 4 guage kit for $33. Total price $375. I found these prices online at different places. Later a couple of Rockford 10's in a sealed box with a Rockford 500 watt rms amp. What do you think and for under $400 what would you go with?