the 8 speaker setup is as follows:
two 6.5" inch speakers in the doors with 2 4" speakers mounted on TOP the 6.5" speakers. (for a total of 4 speakers)
2 tweeters also in the door panels (toyota counts these as speakers, hooray for marketing
)
2 more spakers in the rear.
this gives 8 speakers. the wiring diagrams are the same for both the 6 and 8 speaker setups (really 6 speakers and 4 speakers...tweeters are NOT speakers).