Spiaghi is definitely a great 2 star, but not sure I would say the best. It really comes down to what you are looking for. Do you want a throw away card, a card that can damage, some of both, damage reduction, pill manipulation, etc.

My question is, which clan gives the best 8* (four 2*'s) in UR. This is non-CR and fully evolved.
The reason would be for getting the most out of a another half deck
With the new addition to Junkz, they may have the best 8* half deck out there, but there are other contenders.

Junkz = Gil, Dreen, Veenyle, Sentogen (even Dash works)
Junta = Dean, Wardog, Thormund, Winston
Montana = Spaighi, Prince Jr, Filomena, Ficcanaso (even Ricardo works)
Pirana = Hawkins, Hawkins Noel, Tula, (Spycee? - maybe Trey?)
Nightmare = Eadh, Phyllis, Mawpin, Sheitane (Hel possibly)
Bangers = Graf, B-Ball, Massiv, (Bennie? - Gyro could work)
Pussycats = Bridget, Wanda, Ella, Feelyn (maybe Effie?)
Jungo = Pegh, Mindy, Wendy (Elea?)
All-Stars = Jessie, Stacey, Ashley, (Flo? or Cesare? could work)
Freaks = Esmeralda, Hula, Harleen, Soushee
Rescue = Steve, Krash, Lea, (Vinny? - not Larry due to half deck)
Sakhrom = Nimestiec, Wakai, Na Boh, (Lunatik?)
Skeelz = Sasha, Redra, (Wilhem?, Liam? - lots to choose from for last spots)
GHEIST = Zero Droid, Arkn, (Platinum?, Ludmilla?)
Sentinel = Lehane, Tobie, (Aurelia?, Rick?)
Fang = Chan, Sakazuki, (Yumi?, Unagi?)
Roots = Arno, Jeto, (Miken Moore?, Ben?)
Ulu = Taigo, Gabrielle, (Warren?, Jeff?)