Glad you found your way over here. Do you have access to an OBD 2 scanner so we can figure out what code you are getting.
Here's a rundown of things to check
1. LIM gaskets- A common symptom of the lower intake manifold gaskets is the car using coolant. Under the oil cap it will be a milky white substance from the oil and coolant mixing. The LIM's also leak around the edges.
2. Coolant elbows - Give them a once over to see if they are not cracked or leaking.
3. Transmission Filter & Fluid - I would recommend as routine maintenance to replace the transmission filter and fluid (depending on mileage of the car Dex III vs Dex VI). While doing that it is common to install a shift kit (transgo) to help the trans and give you quiker/smoother shifts.
4. Oil change - I would put some fresh oil in this bad boy. I use a synthetic oil and a good filter.
5. Suspension - A common issue is the front sway bar cracking by the endlinks. Speaking of endlinks Moog makes a nice set if yours look worn. Moog typically makes good replacement parts.
Items 1-4 are the first things my brother and I did on his when he bought his. If I forgot something hopefully someone chimes in.
You can always PM if you need anything.
Speaking of headlights you can get some TYC headlights cheap on rockauto. I do like the OEM corners as the reflector ties into the gold. But there are some clear corners. The DEPO one's are the ones to get on ebay if you want to change up the look a little.
I think he's referring to something like this for the front valence.