Yeah, Invincible has the speed and fight edge, but Colossus has strength.
The highest documented weight he(Invincible) was seen pressing was around 400 tons.
Colossus was states as lifting 1.5 tons per pound or some such nonsense, so his range is in the thousands.
And recently Invincible and his little brother were struggling with that Viltrumite ship they flew through. Not sure, but I think the ship Colossus caught during Secret Wars..while still injured, was bigger.
Invincible should be a good bit stronger than he was when he benched the 400 ton weight.
I'd say his in the thousands of tons as well now. He and Colossus are probably quite close strength wise but Colossus edges him out.
And regarding the ship, wasn't that right after Mark healed from very severe injuries? Also, I recall them grunting a bit but that being about it.