Well, one of the quickest Strat mods is modifying the treble bleed network on your volume knob , which is restoring some high-end when you're playing turned down — if you have one, and which kind you have, can vary wildly. You could also mess with the cap values on the tone controls, to make things brighter or darker. Or maybe swap the five-way switch for three toggles, or alternately push-pull switches on your tone and volume pots, so you could play with combinations of pickups that you normally couldn't, like neck+bridge or all three at once.

But for you, Tada Riina, I would recommend putting everything back exactly where you found it and never mentioning this to anybody.