Yes, the scale of the financial support of election affects both policy and outcome
Corporations are founded on the basis of making profit, so to argue that donations made to political parties is not for some kind of gain, that will directly or indirectly lead to profit is naive. Big corporate interests often donate money to both sides of all major parties in the run up to elections, so they are obviously not supporting the parties campaign. In effect they are playing the parties off one another, cutting donations if party policy is not to their liking. This has had the effect of major parties falling in line with policy that favours big sponsors, or risking not only having their funding cut but a relative boost to that of their opponent party.
A clear example of this was the prospect of gambling reform in Australia, in the run up to the 2013 elections. Public opinion was overwhelmingly behind reforms to the current law concerning poker machines, but a big shift in funding and pressure from gaming industry lobby groups effectively took the issue off the table. As campaign contributions control, to a large degree, how effective the campaign a political party can pull off is, and as this usually amounts to who wins an election no one is willing to challenge something such as this when it happens.