Good day forum members...

I don't know if this has been discussed already, but I can't seem to find the proper loop.

EGR - to blank/block or not to.

Sub-forum member owners of Montero's / Fortuner's / Everest's and the other diesel SUV's swear that there are benefits and some do not.

My question is WHY would the manufacturers (Mistubishi / Toyota / Ford / Hyundai / Kia and the others build engines that incorporate EGR's only to have it blocked / blanked by modifiers. (again this is a prerogative of the owners)
There has to be a reason why EGR's are there in the first place and that's to reduce harmful emissions.
HOWEVER, if you leave it unblocked / unblanked your engine produces black smoke and the manifolds accumulate soot.
So what gives???

There are mechanics who simply say "let just clean or replace the EGR when it becomes dirty, madali lang yan"
Modifiers say "blank / block it immediatetly, it will save you money in the long run. No smoke and faster and stronger accelartion"
Owners however have mixed results:
Negative - CEL, fouled up ECU's, melted plates, still emitting smoke, etc
Positive - no more black smoke and faster accelartion , no EGR to clean and manifolds stay clean too.

Then there is also the question of passing the smoke emission test for registration.
If you blank blank / block, will your engine emit higher NOX reading coz the EGR is not doing what it is intended to do, which is reduce unwanted emission.

I know this is debatable.
Appreciate your comments / inputs / and learned suggestions.

Thanks !!