Welcome to the forum. Don't want to step on anyone's toes but my two cents.
Not sure where some of these prices come from tbh unless you guys are actually paying £300 for a single camshaft from blank and £1000 for gas flowing of a 4 cylinder head, be it 8 or 16v.
Also, you won't really see any gain from an adjustable FPR unless there's something wrong with your existing regulator. Steer clear from the FSE brand ones, I've seen them fail miserably at trying to hold there set pressure on many occassions - they jsut adjust themselves!! It's essentially a cheap way of adjusting the fuel flow when running larger injectors instead of having it mapped properly on standalone and even then you'd need a rolling road to set and adjustable FPR up properly.
What does porting the exhaust gasket mean?
I agree with all the other stuff mentioned though but do try and do as much of the work as possible yourself, it will save you a fortune in labour and you will learn along the way. Fitting a panel filter and exhaust system (cat-back at least) is all very easy stuff with a few basic tools and a great place to start. Cams will involve timing and reshimming and is best left to a garage if you don't know what you're doing.
Oh and make sure your engine is running right in the first place. You wouldn't believe the difference a fresh set of plugs, leads, fresh oil, oil filter, fuel filter and a bit of injection cleaner can make.