Need Help Switching To A Lighter Racket

Need your help please. I am currently using a 90 sq, 12.5 oz (350 gram) 16X19 racket and thinking about switching to a lighter 90 sq, 11.8 oz (330 gram) 16X19 racket or a 95 sq, 11.5 oz (320 gram) 16X18 racket. Can you tell me what will happen/impact to my serve/strokes/volley....and my game overall. Thanks!
 
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