I built the original Protar kit when it first came out. Assuming the decals are the same as the Protar ones, then they fit ok. I fitted the windows in to the body (take time to get them to fit well) and then put the black surround decal on top and it seemed to go well. The kit represents the launch/first race version.
The LC2 is indeed a fab car, it just seemed to have bad luck. In 1983, the car had Pirelli tyres, but they proved troublesome due to the aerodynamic load put on them, so later in the season they tried Dunlop tyres. The problem was the LC2 had been designed around the radial Pirelli tyres and the Dunlops were cross ply tyres. This restricted their competitiveness. In 1984 and 85, they had lots of reliability issues, but were finally using Michelin radials and the car performed really well. In 85, the would have won at Monza, but were in the pits for refuelling when a storm brought trees down and stopped the race! They did have a couple of wins including at Spa in 85, which sadly was the one with the fatal crash of Stefan Bellof.
In 86, the LC2s were really competitive again, but Lancia was also struggling with taming the S4 Group B rally car and sadly they had lost test driver Giacomo Maggi, who was developing the LC2 in a pre season crash. A single car was entered and the last race for the factory team was at Silverstone, where the car kept the Porsches and Jaguars behind until another problem intervened. The car was repaired and then did the fastest race lap, before Lance withdrew from Group C altogether. There was talk of Rondeau taking over the LC2s, but this came to nothing when Jean Rondeau was killed on a rail crossing.
The result of all this was a fabulous looking car that was always fast (lots of poles and fastest laps), but it just didn't win enough! I was really pleased to see them push the Porsches and keep them honest!