Bridged Rectifier mounted on Heatsink - to isolate or not?

I plan to use Vishay GBPC3502-E4/51, Bridge Rectifier, 35A 200V, 4-Pin GBPC for F5 power supply and plan to mount them on the main heatsink sharing with F5 amp, or probably on the base plate of the chassis
Shall I isolate them with mica sheet + thermal compound? or just mount directly with thermal compound?
 
Ideally, you want to keep any signal lines away from a bridge rectifier, as you could inject noise. Keep as much distance as possible from rectifier and any PCB's. If you have a picture of your setup, I'm sure people will chime in.