improving an SD33

[MQowner]

hi guys, i own a 82' MQ SWB SD33, i love the car to death, and it's in one of the best conditions for an MQ i have ever seen, but after 32 years of running the old girl seems to be getting a bit tired and problems start arising here and there. i was wondering if anyone could give me suggestions on squeezing out extra power/making the engine run smoother (i understand the only real way to get performance is to point the thing downhill). maybe advice on if things like a performance 2 1/2 exhaust kit and extractors, etc. are worth installing. any and all suggestions would be great, thanks in advance.