oil type? and other Qs from an MB newbie

I just bought a '90 300TE with 148k miles. I had an '84 Volvo 240 for 14 years and 252K miles. I always used 20w-50 and changed my timing belt and water pump every 60k miles.

Should I do the same with the 300TE? Also, any other advice if welcome!

Keep in mind I live in Florida and would rarely, if ever, take this car into cold winters.

Thanks,
Greg