i have fender mexican if i change it pick ups what will i change in the tone (mines are original). And what do pick ups change
you could get some mini humbuckers (Duncan lil 59 is great or JB Jr) for a thicker sound. your post is too vague to provide you with any kind of valuable help.
pickups can change your tone, depending on your effects (if you use any) and amp.

your question is really general... what sort of tone are you after, and what amp do you have?
What kind of tone do you want, what amp are you using, and how much would you be willing to spend on the pickups?
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Pickups would change your tone. However if you have a not so good amp it won't be very noticeable. Depending on your budget and styles you play depends on the pickups you need. But I'd suggest as would many others is to save up and buy a decent tube amp if you don't already have one. Some brands of pickups would be Fender Custom Shop, GFS pickups, Seymour Duncan, Lindy Fralin, and some more that I can't remember right now.
Agile AL3000
Douglas WRL90
J&D Strat
Squier Tele
Sammick TR2
Douglas Draco
Peavey JSX
Bugera V5
TS, we gotta know the amp.

In MOST cases, yes pickups will definitly change your tone. It all depends on how much it's going to change your tone that matters..
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