Uh ... Chris, the diode in the red relays, and the resistor or diode in standard DIN relays ... is across the coil, not the contacts!!! Suppression diodes, as they are commonly referred to, have nothing to do with contact arcing ... they are to suppress the high-Voltage inductive spike that would normally be introduced to the +12 Volt power bus and cause havok to semiconductor devices spread thoughout the electrical system, such as CDI units, factory alarm control boxes, etc!
Back to fuse boxes, etc. ...
If the fuse blocks are cleaned annually ... polishing/rubbing compound on the fuses to burnish corrosion, followed by cleaning with Q-tips and Brakleen, then a coating of Dow Corning 4, 4X, 111, or 112 Silicone Grease ... you won't have any problems with the OEM fuses or blocks!!!
ATC fuses and blocks aren't immune to problems in 20-year old cars, either, though the fuse selection is much, much better! I have seen '80s cars with partially-melted ATC fuse blocks ... and if you want to talk about a real nightmare ... just try doing repairs to a USA-made auto fuse block and wiring harness after being overheated!!! ATC fuses do have more contact area than the OEM German fuses, but you are still only talking about the same equivalent connection as a single 0.25" Faston connector at each side of the fuse ... hardly ideal for high-Amperage circuits of 25 A or more! For those, you should really use the Maxi-fuses which are the equivalent of 0.375" Fastons on each side!
Last week I posted a message about a modular ATC fuse block, but I mistakenly referred to Littlefuse as the mfr, when it should have been Bussmann ... the 15660-series on p. 17 of the following catalog is what I was referring to ...
http://www.bussauto.com/shared/library/catalogs/Buss_Auto-Fuse_Cat.pdf