The LCD display on my '97 ES300 was also bad.
I thought I'd just go the easy route and replace the head unit.
I had a new Pioneer Premier deck installed.
When I got in my car to drive away from the shop, I noticed a couple things:
1. When the engine was off, there was no noticeable change in sound quality (from the old unit to the new one).
2. When the engine was on I could hear my RPMs on my speakers.
I asked the install guy about it and he said that they would have to re-wire the car to make it sound right.
And if I wanted to use a subwoofer, I'd need to replace it with a 4 Om sub and get another Amp.
So I decided instead to just buy the replacement LCD screen and have the shop undo the changes.