My question is this, between 165 grain and 180 grain 40s@w is there a noticeable difference in felt recoil

For me with my Shield, the 180gr doesn't feel as snappy as the 165, more of a hard push than a sharp jump. Don't know how accurate that description is, but that's my perception of it.

I can't tell the difference in my 40c.

In my hands, there is a difference in recoil. I shoot both weights in factory ammo on occasion and the 165 does seem sharper in kick than the 180. If I recall, the published energy figures are higher with the 165. I shoot Gen 3 Glock 22s and 23s.

It depends on how it is loaded. At equal MV, the 180gr kicks harder.
At equal Power Factor (momentum) the 165gr has more MV and energy and kicks harder.
In competitions where Power Factor is required, 180gr is the favorite.

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Science plus Art

Interesting, I don't notice that at all with equal power factor. I've loaded 180g 40 bullets to shoot 730 fps (2.7g Clays) and 120g 9mm bullets to 1100 fps (4.2g Unique) and shoot them through the same gun (M&P40 swapping between 40 and 9 barrels) and the recoil is the same as far as I can tell. Both are PF=132.

I've used this as a standard (also used 3.0g Red Dot) so I can get a feeling of what a 9mm version would feel like with other 40 cal guns.

I thought that the competitive groups try to run things equally by trying to set equivalent recoil. That's why they came up with Power Factor as the equalizing quantity and not muzzle energy.

For historical reasons, Power Factor (momentum in odd units) was adopted, primarily because the ballistic pendulum was the only affordable method available at clubs to measure handgun power. Even now that usable chronographs are readily available for $125 and nobody uses the ballistic pendulum at matches anymore, the usage stuck.
I don't think anybody would say that, in equal weight guns, a major .45 ACP has the same recoil as a major .40. .40 rules in limited because the magazine holds more cartridges.

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Science plus Art

I felt like the heavier bullets in the 40 I used to own, had less snap than the lighter ones. It is all perceptive. I eventually traded the 40 for a 9c and shoot 9's and 45's now. Just could not fall in love with the 40.