engine mod path questions and whatnot

[Fishguy]

Since my car will be stored at home all the while im at college

i have plenty of time to think about a few simple mods to get a little bit more power outta this very nice little car

specs:
1984 944 (european spec, w00t!) with 26,000 miles on it (no joke!)
now, its been taken pretty good care of (though since i got it, the oil pressure seems to run low, frequently going to 1.5 and 2, after it runs for a long period of time (though when revved up to anything past 2 k rpm's, it goes all the way to 5 constant)
is that something to worry about? or could the pressure gauge be misreading do to underuse? that seems to be teh only problem with this car, its got too few miles, and things like the seals dry out (ive got a wee bit of an oil leak do to a leaky seal - i think) I had to get the Clutch slave cylinder replaced becasuse the seal on it failed and leaked alll the fluid out.. the PO said that the seals might've dried out do to underuse (he only drove it 3 times in the last year before i bought it from him)
though it seems to run really well, and seems to have a decent enough amount of power (plenty fast for me!) though you cant expect a whole lot out of an 8 valve NA 4 banger, its still good

but anyway, I would like some advice on planning upgrades to this car
I found 9xauto.com, they seem to have a lot of good info and stuff at reasonable prices

It seems i have to start with changing some parts that might be useful to have changed

like fuel filter, intake boot, fuel pressure regulator & fuel damperner

what are all the little things that need to be done before i actually do teh performance mods?

so far fuel filter, intake boot, fuel pressure regulator & fuel damperner (though i think the last too probably dont need a change yet),

then K&N Oil Filter + Mobil 1 oil (what kind is the best for summer use? they have the 0 w30 "european engine" stuff, or should i go with the multiengine 10 w30?)

ok then will that be all i need to do to actually start doing performance mods?

what would be good bang for buck mods ? new camshaft? new Muffler? upgraded exhaust?

i was thinking to start with a K&N intake kit, including bracket and adapter from 9xauto.com

then a set of Nology Hotwires and Silverstone sparkplugs

after that, i was thinking of a new ECU from Powerchip (though they are $450, are their cheaper yet still comparable chips out there?)

please give you all your reccomendations as to the best way to get more power with the best bang/buck in mind

thanks guys!