2002 Nissan Altima Exhaust LEAK! MLS leaking.

Im hoping you can help with this guys:

I have a 2002 Nissan Altima 2.5L engine. The car started running rich and very low mileage due to an exhaust manifold gasket leak. So I went and bought an "MLS" gasket, the ones that are hard and metallic, it came with 2 layer of metal welded on 5 points. The gasket was Beck Arnley and that type of gasket looks exactly like the stock ones, MLS.

So I went and installed it, but the car still leaks. How did I noticed it leaked? Well, while the engine was cold, I hooked up my home vaccuum cleaner to the exhast tailpipe with duct tape and turned it on.

Definitely there was hissing coming from some points where the exhaust manifold gasket was, some louder than others. Did this with a piece of hose and hearing it with my ear. Even when engine was hot, the leaks were apparent hearing them through the hose. When the engine was hot and running, the leaks were louder hearing them with the hose.

The gasket was brand new. Due to the age of the car 135K miles, will this type of gasket (The composite FELPRO type) will suite my car best instead of the flat MLS gasket?

Im thinking FELPRO the composite gaskets. The exhasut manifold which has the cat integrated, is working fine, no blockage, so I dont want to replace a very expensive part.

Ive heard for MLS gaskets to seal perfect, both areas (manifold and cylinder head) need to be machined 100% flat, and I didnt machined mine, so Im guessing thats the problem.

I installed everything according to the manual, torque specs.

What do you recommend?

Is it wise to use 2 composite gasket? Obviously Felpro. One on top of the other on my exhaust manifold? What about the heat?

Ive used Felpro composite gasket on the past on other cars, like the intake manifold and plenum, egr valve, throttle body and seals great.

Thanks you so much for your help!