Spark plugs DIY questions on Sonata99

Hi all,
I have replaced spark plugs recently for my Sonata 99.
I bought NGK spark plugs at Napa, confirming Napa's database. But the part number does not match exactly to the HMA web site
recommendation.
After the replacement, it seems that the engine is little bit louder now. Is this normal?
What can make the engine louder?
A disturbed throttle cable adjustment?
Out of heat range spark plugs?
Or, the computer being turned off, it forgot my driving style and need time to adjust?
Do I have to do additional things other than just replacing spark plugs, such as cleaning throttle body?
Thanks, Jae.
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Is the air cleaner lid sealed properly?
4 or 6 cylinder?
Dunno, doesn't make much sense, really.
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6 cylinders. 60,000 miles on it. The replaced plugs look good, except one with a worn out tip.
Maybe, it is just my wrong perception. In fact, I was expecting the engine to become quieter or smoother (so much for my ignorance).
But here are my concerns.
First, the throttle cable was touched in order to remove the intake surge tank. Do I need an adjustment on the two little bolts that hold the cable to the arm of the surge tank? Does this make sense to anybody?
Secondly, I re-used the intake surge tank gasket (which looked okay). But, HMA web-document says "don't reuse it". As I torqued all the bolts following the specs, it would be all right.
Thanks in advance for your insights, Jae
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As long as there's just a little slack in the throttle cable, that should be okay.
If you're not misfiring at idle, your surge tank gasket should be okay.
Check the things that could affect noise level. Make sure the breather hoses are connected. Make sure the air box is sealed over the air filter, etc.
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