The 3.0L V6 in your Toyota Solara has a Timing Belt, and Toyota recommends replacing the Timing Belt at the 90,000 Mile Service. It is a good idea to replaced the waterpump and the tensioner at the same time. If the front engine seals are leaking, or even seeping oil, replace them at the same time as well
Trust Murky here. Do all seals ("o-rings" etc.) and water pump. You'll save yourself time and money. I just did the oil pump gasket and seal, and water pump and wish I had done everything when I had the t-belt changed. T-belt - $10 bucks, labor to get at it: expensive.