Cool dude! Actually at one time I was going to build a Group 5 X1/9 but built a 124 Coupe instead. Of course you realize this was more than a few days ago...
The coupe was fun though, lowered 3", 215/50-13 T/As, etc. Hard to push the loud pedal to the floor in first gear before hitting 11,000 r's. Sounded like a pack of chainsaws on steroids. Spent a buttload of money too! Bought the car for $200 and had almost $9000 in it two months later. And for me that was all just in parts and machine shop expenses (1979 dollars, too.) Of course being a Fiat it rusted to the ground two years later in Florida and I ended up selling it for $900...