You're not going to get around the need for registry settings on the client side to improve the performance of PDMLink. However I believe you can setup policies that will make all those settings. (Anyone that has done this with policies should chime in here.)
Attached is what I think the settings should be.
In regards to Chrome, Firefox, vs I.E.
I don't find that for general browsing Firefox is any faster than my IE. Chrome is much faster. However ProE uses I.E. internally for the embedded browser. When you're making changes to the registry you have to make sure you make the changes for xtop in addition to IE or you will not see any improvement inside of ProE.
The download performance tweaks need to be tested by running ProE in debug mode and then looking at the uwgm log files for the start and ending of the download.
In a shell you can search for Background in the uwgm log file and get the start and finish times.
<shell prompt=">findstr "Background" "<proe home=">\Log_PROE_28_05936_2011_10_17_14_36_21_000001\uwgm.log.1"