So I bought my new Madone SL6 in March. I love the bike but its no secret that its heavy. In fact, 20.8 pounds heavy with the blendr garmin mount, garmin power-meter pedals, and 28 mm tubeless tires. Anyone managed to get their madone SL frames to lower numbers? What are the most cost-effective changes that keep the aero qualities? Also anyone know if the weight for the integrated bar/stem is much different? I have wanted to upgrade but read somewhere that its significantly heavier? ( may still be worth it even if though).

I know someone will say that the weight doesn't matter. I bought a heavy aero bike because I don't prioritize weight. But if you can optimize weight while preserving the fit, ride quality and flats speed of my setup then why not? It does help with accelerations and the feel of a bike sometimes for sure.

Put lighter parts on it. Preferably ones that rotate.

21 lbs, eh? What are your cycling goals?

Start with wheels.
Stock are 1900g, look for <1500g ones.

What gruppo does it have? I swapped out the stock Mavic Aksium clinchers on my CAAD 12 for Mavic Ksyrium Elite UST and that saved weight. If I swapped the stock 105 for Ultegra or SRAM that would save weight as well. Right now it's 17 lbs 10 oz. It really comes down to how much you are willing to spend.

Nothing too serious. I'm not racing or anything like that just try to join local club rides every now and then and want to feel more fit. The motivation is just for feel. Current ftp is 225 at 170 pounds ( was 160 a few months ago logically you'd think that's where id start 🤦🏻‍♂️&#128514

Your right. I was thinking wheels are one place. But not sure where to go after that. I can have lighter cockpits but I like their blender system and how neat the front end is which is probably more watts than any weight savings there. Not sure if their integrated cockpit is any lighter ( I read on a firm that it wasn't though can't find the info myself. )

Lighter wheels, changing accessory mount materials to something less bulky & made of a composite material, changing crank arms out (if feasible) for composite, trimming seat post (within reason) to be shorter, seat, & pedals.
Could go the extremes & replace certain hardware out, but you'd have to outweigh the risks.

Why not make your body lighter by loosing 5-10 pounds of fat instead of wasting money on lighter components ??

Frankly I like how I look better at this weight. Close to 160 people told me I looked too thin. I'm 6 feet tall ... It's not an abnormal weight for me but I've consistently been told I look healthier at my current

People are starting to recognize that the eating disorder-like obsession with body weight for cyclists is not a good thing for long-term performance. OTOH, a lot of us could stand to lose some weight. It's hard to balance sometimes.

For making a bike lighter, there is nothing like buying a scale and figuring out what the problem parts are. Cheaper cranks are often a lot heavier than more expensive ones, that's probably a good place to start.

Should of bought an SLR to begin with.

I get what you're saying...I am also 6 feet tall and weigh 163 pounds. I wouldn't want to go any lower than that.

I changed the wheels on my Madone for Roval Rapide CLX's at circa 1400g. I intended to swop out the Ultegra for Dura Ace... then decided not to. Why? My 2kg lighter Wilier makes very little difference overall.
Sure, the lighter bike feels better on long, steep climbs and my PR's on those are with that bike...but the Madone is not far away and overall, I think it is quicker as is; I sprint better on it, I TT better on it. It is my preferred bike to race.

I'm currently training for a race next month. I want to drop 2kg...from myself, not the bike where I think it will make next to zero difference to how I do.

I used to have Trek 5.5 Madone SL Project One years ago. Tried to weight weenie it on a budget, and got it down to just under 15 lbs..

List of the parts:
Frame: Trek 50 cm OCLV 110 carbon 1100g? est.
Fork: Bontrager Race X Lite 374g
Headset: Chris King Threadless 126g
Seatpost Clamp: Krex 34.9mm 12g
Seatpost: Hylix Zero Carbon + Ti (cut) 130g
Seat: Selle SMP Chinese Knockoff 128g
Stem: Uno 7 Super Lite 83g
Bar: Bontrager Race Lite VR 230g
Bottle Cages: Profile Design Karbon Lite 27g x2
Brakeset: Shimano Dura-Ace Dual Pivot brakes 317g
Front Derailleur: Dura-Ace 82g
Rear Derailleur: Dura-Ace SS 182g
Crankset: Dura-Ace 761g
Bottom Bracket: Dura-Ace 98g
Chain Rings: Dura-Ace 39/53 teeth 143g
Chain: Dura-Ace 163g
Shifters: Dura-Ace STI Dual Control 378g
Cassette: Dura-Ace, 10-speed, 12 - 25 teeth 200g
Wheels: Farsports 38mm 1260g
Skewers: Ti 44g
Rim Tape: Stans 20g
Innertubes: Vredestein Latex 50g
Tires: Continental Grand Prix 4000 S II 210g
Bike pedals: Speedplay X2 SS w/ Ti spindles 153g

It's cheaper in the long run to buy a lighter bike (frame and components) in the first place than to replace new parts with lighter new parts.

My Emonda SLR.

Okay, then join the clubs and worry about your bike weight later. Positioning and fitness will make a way bigger difference in keeping up than a few pounds off the bike.

If your vitals are good, you feel good & perform good when you're close to the 160s, what does it matter to what people think?

You could always drill a bunch of holes in it. Might save you half an ounce.