You're going to be digging in there anyway replacing the low beam arc-discharge capsules; it's time to upgrade your high beams to the Toshiba HIR1
(Toyota P/N 90981-13066)
It will require a minor base modification, and you'll definitely want to move your DRL function from the high beam to the turn signals, using the
DRL-1. Otherwise, those bulbs will die a miserable death and while dying be rendered increasingly worse for high beam usage.
In all, it's a hefty investment, but definitely worth it.
Make sure the lamps are in excellent, as near-to-new-as-possible condition, and the lamps are
aimed correctly. Your bulb upgrades will be for naught if your lamps are in bad shape and the aim is not correct.
If your lamps aren't in such great condition, a polish/reseal of them may buy a little extra time, but depending on their condition you may be better off replacing them with genuine Lexus parts (*not* aftermarket junk).