Hi all,
Me and my dad (126Cab) have tried the 500 Giardiniera stock exhuast on the 126 BIS and it does fit on the manifold ports but the actual pipes are approx 1inch short, therfore catchs the bottom of the engine... but adding a bit to the pipes is a easy mod.
Also the brackets would need welding on from the BIS exhaust onto the Giardiniera once again easy mod..... (stock exhaust bracket is held on by 4 spots of weld)
now off to buy a Giardiniera sports exhuast
http://www.fiat500sport.com/dettaglio.asp?a=0236&t=6&l=ENG&sku=7F27B8CEE#0236 
Ill show pictures when its all done hopfully next week
