This is for my daughters car. Not looking spend to much as the 200sx has 245,000 miles. Locally the used ones has bent valves, I already have one of those as her's the upper tensioner gave up and eat the idler gear and bent all the valve as she tried to restart it.
The lower end looks good just need a head (working) in the $200 range
You could try what I did, but it's kind of a risk. I bought a used head from a junkyard from a sentra with fewer miles than mine. Cost: $100. I brought it to a machine shop and they fixed it up for another $100. It worked for me, but I don't know if I just got lucky