I am thinking of plugging my LIM but I may replace the UIM anyway....I can buy the Dorman for 100.00.....any idea where the cheapest place to get the sleeved APN one is ?

If the UIM is in good shape you can clean it and reuse it, I had to replace mine because when I took the throttle body gasket off the plastic of the UIM that surrounds the gasket broke off.

The Dorman UIM is only 64.79 at rockauto.com, DORMAN Part # 615180

If you replace the EGR stovepipe IMO you really do not need the added steel bushing, the EGR gasses should not be a problem with the reduced diameter EGR Stove Pipe.

If you really want that steel bushing you can spend 90.00 and get it from here.
GM Intake Manifold Kit

Could I remove the UIM and NOT remove the throttle body ??? Someone said if you are going to re-use the UIM do it this way.....So the I could pull the UIM plug the holes in the LIM and reinstall the UIM and same gasket ?

Yes you can remove it with it still on there, that is what I did, I removed the throttle-body once I had the UIM off of there to clean it, and polish the butterfly valve.
I would not reuse the old gasket.

If you are reusing the UIM I'd not risk removing the throttle body, as when you replace the gasket you may encounter the same thing I did, then you'd have to replace it anyway.

so are you saying I should remove the plenum with the throttle body left in tack...plug the lim holes, use a NEW UIM gasket with the old plenum and re-install all w/o removing the throttle body ?

That is one way of doing it yes. But now would be a good time to remove the TB so you can get at the butterfly plate and IAC area to clean it good.

ok I can buy the AC delco UIM gasket only for like 18.00 on Amazon...this should fit my intake no matter what make the intake is correct ?

Correct.

as i said numerous times, the chances of stuff being able to be reused is slim. the one on my 98 was redone around 03-04 and still last year when i had to do it again the webing on the upper was blown out around the tb area and the lower intake gasket was blown out around the intake ports

if in 03-04 you used the "new style" uim and lower gaskets why did you have to do it again ??? How many miles did you put on it ??

I can tell you this...my last 3 3800 series 2'* I have run to over 200k and although I did do the uim'* on 2 of them I never touched the original LIM gaskets on any of them...the one Park Ave is still being driven daily with almost 300k on it.....

maybe i just lucky,,,,the only thing I did when I first got every one of them is flush the coolant and refilled with Prestone mix with any color,,,,weather that helped or not I cant say but I never had issues.....wonder why