yea, the symbiote gives Brock class 11 strength. Spidey already has class 10. If Parker accepted the symbiote, he would be class 21. he'd also have an enhanced spider-sense, and unlimited webbing(isnt really an advantage, Venom has it too). Spiderman permanantly bonding and cooperating with the symbiote would be a match even for Carnage.
You can't go ahead and assume that Spiderman has bonded with the symbiote because that screws up the whole point of this thread.
Spidey having the symbiote has his advantages and disadvantages. Spidey was still getting an understanding of the suit when he had it. It would do things that he didn't know it would do, but he accepted it because it was really interesting to Peter Parker.
Yes he gets the strength addition on top of his super human strength...that we can conclude. But you have to assume that Peter and the symbiote do not act as one. It throws him into fits of rage...he wants to kill just like Venom does...but Peter's conscience has so far gotten the better of it. So the best way to consider this match up would be to take Spiderman right before he got rid of the suit.
I'd still give this fight to Spiderman because that point about the strength is just too good to go against, and for other reasons also. The suit would add to Spidey's speed, strength, well basically reflexes in general. Plus Spidey is amazingly resourceful, he's smart, pretty well connected, a hero.....he's really just too many things that Venom isn't.
In terms of physical strength only the alien when separate from Spider-Man had the potential to reproduce his strength exactly and when attached to Brock it straightaway added Spider-man's strength to Brock's considerable natural strength. So if we were to take Spider-Man with the alien from the past and put them in a future timezone containing Venom then there is no question that Venom would have the greater physical strength.
But yes, Brock was never the sharpest tool in the box. I should think that Parker would win a contest of resourcefulness hands down.
Spiderman does not want to kill with the symbiote. The symbiot feeds off feelings. When attached to Brock he wants to get back at Peter Parker for the humiliation Peter caused when revealing one of Brocks storys to be a fake. Brock was praying because he was asking for forgiveness for the sucide he was about to commet when the symbiot connected to him for it was the church bells spiderman tried to use to get the sybiot to unconnect. The symbiot then fed off the feelings of hate for peter parker but also hate for spider man for when the symbiot connected to Brock Brock found Peter Parkers Dual Lifestyle Of spider man and Peter parker. He only wants revenge on pete and infact stops some crimes from happening.