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Question: Choice between SPS 600 vs SPS 600C

Santa gave me a Pioneer DEH-P4100 (200 watts) player and looking to upgrade with new speakers in my 97 pathfinder. I need 4-6.5 inch speakers and looking at Alpine's gear. Trying to decide between SPS-600 and 600C...a difference of $50 a set.
Is the extra cash worth it in sound quality?