conor - 8:10 am on Jul 27, 2010 (gmt 0)

If you can get rid of half of the backlinks (just the fact that you can makes the quality questionable and doubtful that they were editorially given) particularily if they are run of site, repeating anchor text and low quality you should and even more so if they could look they were paid for.

But its also important to concentrate on getting some (just a few could be enough) quality IBLs with not that optimized anchor text to inject a bit of trust again.

Just changing the bits on the new site that you think are the problem may not be enough.... Rolling back, letting the dust settle and taking a hard look at the new changes then carefully reapplying the changes that look safe one by one is probably the way to go