As with all Diablo, starting from 1999 the pop-up headlight units were replaced by glass-covered fixed ones.
In addition, the interior redesign for the 1999 model was used, the seats were a little different and dual airbags became standard, the passenger airbag neatly built into the dashboard this time. Engine power climbed to 530 Bhp on all models and the entire Diablo series received 18 inch wheels and bigger perforated disk brakes front and rear with a Kelsey Hays ABS system using multiple sensors as standard issue.
As with every Diablo built in Sant'Agata, the engine was still completely finished by one person only, being completely responsible for it, the space tube chassis was constructed by Marchesi in Modena while the aluminum panels used for the front hood, the doors and the front fenders were supplied by Golden Car in Cuneo who also worked for Maserati. The composite body panels used for the engine cover and the bumpers were made inside the Lamborghini factory; they even have a complete Autoclave system installed to construct composite material based panels.
The cylinder heads used for the massive V-12 engine were finished at Lamborghini but Fonderia Scacchetti made the base for them, the crankshaft was still cast in one solid billet and then made into the high finished item built into the heart of the roaring engine.
Once the engine was finished it was tested on a test bed, outside of the car it would be built into, only after the engine was fully tested it was mounted in the final car. Each engine was completed on order for one specific car, so you could check serial numbers to see if a second hand Lamborghini still had the original engine or if it was replaced. This way customers could order different compression ratio's on their car, and even different gear ratio's were possible. Three gear ratios were 'standard', a special one to obtain a higher top speed, the normal one and a special one for red light racing, the top speed was a little lower but the acceleration was faster.
By the way, the 1999 engine type was recognizable by an inscription on the central cover over the air intakes on the engine; the new engine said 'Valve Timing Management'. These 1999 type V-12 engines managed to reach 530 Bhp instead of the earlier 510 Bhp.
After your Diablo was finished, it was taken out on the road three times, each session about 60 Kilometres in length, to check if everything was correct. These testing sessions were used to modify the suspension and roll bar settings and to alter the engine management system if needed. So it was very normal to get a brand new Diablo with already some 'delivery-miles' on the counter, which in case of the SV model was finished in white using black digits.
The Diablo SV 1999 was actually one of the final evolutions before the Diablo GT was built, but it still used the famous signature of Marcello Gandini on the right side.
Strangely enough, the Diablo SV production was halted for the production year 2000, only the Diablo VT 6.0-Liter remained in production.