Okay...with that many miles you should have atleast a record of the timing belt change. I have a 92 GS-R and I had the timing belt changed just in case. It was some money but hell, better safe than sorry. My GS-R is great and I just have a few minor repairs to do on it. But as always, if you want the best out of it... Start with the basics. Use full synthetic instead of convential motor oil. Use 91+ octane and just have the basics covered. That is my suggestions before really doing any work with it. And always run synthetic oil... Guarantee power gains and/or increase mpg. When I say basics---it includes: all the fluids replaced, leaks checked, spark plugs, tire pressure...just do a full tune up to ensure that nothing is wrong.
That is all I can say.
PSI
92 GS-R
89 DX Civic Hatch