OK. The HGT 147 was the original model then when the MK2 Bravs came out the engine had been tweaked up to 155 for both the HGT and the FIAT Coupe.
As for Bravo Abarth, there's is no such model simply and Abarth bodykit that was available at extra cost from new. Abarth really means nothing anymore but used to be a styling / tuning arm linked to FIAT, much in the saem way that Ghia and Cosworth are / were related to Ford. For old FIATs, the Abarth name meant that it was the sporting version that had been tweaked by Abarth. Now it means it's the standard version that you want to buy with a few bits of plastic stuck on.