the bloatware included can slow it down by as much as 60% compared to a clean install
Actually I'd be hugely surprised if the bloatware slows it down even 10%.
Sure, bloatware IS evil, but its not half the problem a lot of people try and make it out to be. I think it would be wrong to assume that any bloatware issues play ANY role in what ratings a laptop gets during a review. Most reviewers know you can just shut down any running bloatware and clean up that possibility of 10% performance hit. It's not even necessary to un-install the bloatware, just so its not running and taking up system resources.
I'd suggest its a lot better idea to just un-install the bloatware vs taking the time, trouble (and a chance of a botched re-install) than going through a clean install. Still not convinced? Partition the hard drive and do a clean install to the new partition and have a dual boot setup. Now do a performance test between the two versions and see what the difference, if any, is between just having the bloatware shut down and never have been installed.