Nein, gemeint ist: Wenn ich das sage, dann will das was heißen!

Das spricht doch nicht gegen meinen Vorschlag, es hängt von der Intonation ab, genau wie im Deutschen. #3 passt, hat aber einen anderen Zungenschlag - vgl. das muss sogar ich zugeben.

Gibt es muttersprachliche Meinungen?

https://jasperandspice.com/uncategorized/call...

This is one of those books where you have to read the blurb before you start the novel, and that’s something coming from me because I never read the blurb before the book.

https://www.dailymail.co.uk/sport/football/ar...

"I'm not being critical of foreigners, but players' behaviour is different. I know people will say that's something coming from me, but every time they're touched they seem to go down."

https://www.theguardian.com/sport/2000/sep/17...

Not any more. Our best players won't develop into great players until those pitches improve and remember, spectators want to see batsmen hit big scores. Batsmen are the craftsmen and bowlers are the labourers in this great game of ours - and that's something coming from me.

https://blog.auditortrainingonline.com/blog/f...

I suppose talking that through means - just relax a bit. You don't have to be perfect. And you know what, that's something coming from me! I'm one of those people that wants 10 out of 10 for everything. 

https://idioms.thefreedictionary.com/that%27s...

Used to emphasize that what was just said is of even greater significance than might be assumed because of some underlying aspect or context of what one is discussing.

My brother could hit me harder than you, and that's saying something, because he's only six years old!

Even the megacorporation Boogle Inc. is opposed to the new tax proposal, claiming it unfairly benefits the wealthy. Now that's really saying something, considering they'd probably stand to benefit from it more than anyone else.

This is the most confusing novel I've ever read, and considering I did my master's thesis on Ulysses, that's saying something!

https://www.theguardian.com/culture/tvandradi...

KNTV is perhaps the most bizarre thing I have ever seen on television, and that's saying something for someone who used to watch Eurotrash. 

https://www.theguardian.com/tv-and-radio/2015...

“I hate them, fucking hate them, I hate them with a fucking passion, more than I hate West Ham football club, and that’s saying something because I hate them bastards, but yeah, I hate them, hate them with a passion.” That’s a whole lot of hate.

Yes, #1 is fine. There's also:

...and that's something, coming from me or

...and that's saying something

Primland is nicer than the Broadmoor (and that is saying something)!

REVIEW: Primland is nicer than the Broadmoor (and that is saying something)! - Primland Resort, Auberge Resorts Collection, Meadows of Dan - Tripadvisor

That's me saying this now, I don't know if I'd feel the same way in a month or in 10, 20 years.

Lions: Having a song about you is pretty cool - Furlong | BelfastTelegraph.co.uk

But that's me saying it, you are probably best asking him or the people who look after him.

Ex-Saint's 'awkward' warning for England | Daily Echo

Deine beiden Beispiele für 'me saying' sind nicht vergleichbar. Sowohl "now" als auch "but" ändern die Bedeutung. Die Wendung, um die es hier geht, lautet "And that's me saying that".

Aber abgesehen davon gibt es Kontext. Ich wüsste nicht, wie man das in der Aussage des OP missverstehen sollte.