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What is your 1/4 time now? Unless you are in the 10's and trying to squeeze every little ounce out of your car to get it to a faster time then no, it won't effect your times enough for you to notice.
think about the difference in performance when you have a passenger in your car. you can feel it. now how much does your box speakers and amp weigh? make it where you can disconnect it and remove it at the track. may be worth a few hundreths of a second.