OP's taking a while, meh.
So i'll bring up some options for under $100 each since i have nothing better to do.
It's not mentioned if the car's automatic or manual so i'll start with a manual modification:
~$20 used 94-01 Integra stock shifter shaved to fit D-series linkage
~$60 PWJDM Brass Knuckle 530gram shift knob.
I never appreciated my car's shifting until I bought my 240sx and drove a friends manual Scion XB. The heavy shift knob + shorter shifter really changes the car.
Exterior:
Front lip 96-98 replica SiR or CTR (Civic type r) lip & mesh grill, folding side mirrors (each can be probably had for under $100)
Interior:
Integra Cluster (used under $100)
S2k cluster (can't be had for under $100 but is really nice)
Direct seat swap options
97-01 CRV, 94-01 Integra (98+ integra seats are better), Del Sol, S2000, 92-96 Prelude
Interior lighting: follow this chart and order the bulbs on amazon or ebay.
Also, a 48LED panel light is very bright for the dome and fits well. Also get a licence plate light bulb while you're at it, all should cost under $20
http://www.modifiedlife.com/1999-honda-civic-sedan-light-bulb-size-guide/
But before you do any of these, fix current problems