So I got a 98 prelude (auto/non sh) with a short ram aem intake ngk wires, and iridium plugs...

Every time i drive the car, the temp needle is at halfway (normal), however if after driving for a while or after the engine heats up and i stop and put it in park, the temp needle climbs to 3/4 of the way to high. If I put it and drive and go, the needle settles back to halfway, which is trippy. I popped the hood in park and there were no visual signs of overheating or any leaks, so I'm sorta lost, what could be happening???

 

Change your thermostat. I had the same issue with mine after I had put in a aluminum radiator and an autozone thermostate(big mistake). my temps would go up when I would be stopped but go back down when i drove. So I later changed my thermostat with a genuine honda thermo from the dealer and that fixed the problem.

 

okay, money-wise, roughly how much do you think it's gonna run me?

 

If you do it yourself, the price of the part which is $19-$25 depending, some dealers vary by price. It's very easy to do if you have some basic tools, oh and you'll also need a jug or 2 of coolant to refill the system.