Wastegates

[DOA]

Okay then, Ive been looking round this forum for a while and seen all the posts concerning boost controllers and all that jazz and yet I dont see anyone mentioning directly swapping the wastegate on the turbo, or even for that matter just uprating the spring and diaphragm.
So, to get to the point, would it not be preferable to uprate the wastegate to open at higher boost pressures or is there some fundamental problem in doing this on the legacy? Also if it is doable (and I cant see any reasons why not) would it be possible to maybe swap the units in from later imprezas like the sti's and evos as I would think this would be cheeper to get hold of from breakers and the like. the main reason I ask all this is because as I see it all these various electronic and manual boost controllers are rather too large a compromise with regards to fueling and so on as all you are doing is fooling the ECU into seeing something that isnt there (as far as I can see anyway) while if you just swap the wastegate spring the ECU will see the change and maybe not go quite as apeshit.
Possibly some dumb questions and ideas in the above but Im a bit of a noob to turbos and when I used to be interested it was all wastegates and bleed valves which made a damn sight more sense to me.

Oh and this is probably better in another section but I never see anyone mentioning chipping the cars ECU which to me also seems far nicer and safer than just bolting on these (in my opinion) crap big name (read HKS, Blitz and co) boost controllers, FCD,s and so on. I am of couse not having a go at those of you out there making up plans for DIY bits and bobs as thats the sort of thing Id probably do If I had a better understanding lol.

[91White-T]

You're not actually fooling the ecu with a bleed valve, just the wastegate actuator sees less than actual boost pressure, the ECU sees full boost. You could swap the spring but why when a MBC is much simpler to install and take out if you want to return to stock boost.

[DOA]

Fair point to which I will answer, why on earth would you want to return to normal boost levels and mention the small thing called wastegate creep (unless of course a MBC lessens this effect of course ).

[vrg3]

You can of course stiffen the wastegate spring, but a homemade ball-and-spring boost controller can give you similar boost levels with better boost buildup for the cost of a few Mars bars.

Like 91White-T says, boost controllers don't fool the ECU at all. They just "fool" the wastegate actuator.

We've discussed the "fueling problem" before. The short story is that if you use the intake manifold as the wastegate pressure source (irrespective of what type of boost control you're using), you overspeed the turbo creating excessive heat, which the ECU doesn't know about because it's calibrated for the stock turbo setup. If you use the compressor outlet as the pressure source, this problem is for the most part absent.

It is good to be able to return to low boost if anything goes wrong. If your car's a daily driver, that can be important.

For most of our cars, there is currently no good aftermarket chip option available.