loud constant lifter noise. I'm sure it's the lifters, how can I be 100%?

What is your question?

Very loud from the start. It drives pretty well for the noise. I drove it 30 miles down the Hwy to get home after buying it. Not as noticeable while driving it. I haven't drove it since. Don't want to damage it, if it's not already.

What makes this problem better or worse?

It does seem to be worse at start up til getting warm.

How long has your 2000 Suzuki Grand Vitara had this problem?

Was like that when I bought it. Was told before hand.