I'm just really curious to see what [performance/reliability] things I could do to an FC that I haven't thought of, turbo and N/A. I'll start out with just a few of the obvious:

Intakes
Exhaust
Engine porting
Intake/exhaust/ manifold porting
Wastegate porting
Turbo
Intercooler
Radiator
Silicone Vacuum lines
Injectors
Fuel Pump
Engine management
Throttle body mod
Nitrous
6th port removal
Pullies
etc....

add to the list!!!

 

jacobs rotary power pro pack
bigger seals
blow off valve
downpipe
mid pipe
get rid of the stock fan and get a good electric
clutch and lightweight flywheel
larger gears in the *** end
front and rear strut bars
short throw shifter kit
springs, shocks and struts
turbo manifold
dowel pin the seals if you plan to rebuild every couple weeks
and do a bridge port...
plug wires
upgrade the coils
shim the e-shaft, mill the rotors for 3mm seals, cooling passage mod, oil passage mod so it injects more oil in the motor...longer motor life,
nice oil cooler...
looks and interior
fuel cut defenser on a t2
lighter driveshaft if you know where to find one....

 

stickers
giant spoilers
chrome rims

oh wait a minute, those are things NOT to do... sorry.

 

Nice one Kurgan, and don't forget the all important RE Amemiya FC2000 bodykit, a must for any SERIOUS 2nd gen owner.