Question about upgrading socketed uniques

[Amaethon]

I have a shaeled steel driver I would like to upgrade to a martel de fer. However I do not want to do this if I loose the shael as a result. I am also curious if anyone has done this with this particular weapon, as I would like to have an exact idea of what the upgraded damage would be.

Thanks

[adeyke]

Both the sockets and the socket-fillers are retained. No worries :).

Looks in my sig for upgrade damage/defense calculators. For Steeldriver, these are the values:

Low-end (150% ED):
95-145 (120 avg) <-- Great maul
152-247 (199.5 avg) <-- Martel de Fer
82-450 (266 avg) <-- Thunder Maul (elite unique upgrades are ladder only)

High-end (250% ED):
133-203 (168 avg) <-- Great maul
213-346 (279.5 avg) <-- Martel de Fer
115-630 (372.5 avg) <-- Thunder Maul (elite unique upgrades are ladder only)