In 1986, Ferrari introduced the GTB Turbo and GTS Turbo, variants of the 328 designed for the Italian market to avoid high taxes on cars over 2 liters. These models replaced the 208 GTB/GTS Turbo and featured a turbocharged 2-liter engine, evolved from the 208 Turbo but now with an intercooler and a new IHI turbocharger, producing 254 PS. Developed by Nicola Materazzi, who had extensive turbocharging experience, the engine included advanced features like a Cermetal coated cylinder and a knock sensor. Design changes to accommodate the intercooler included a redesigned engine cover with NACA intakes and a rear bumper with ventilation slots. The GTB Turbo and GTS Turbo, with minimal differences from the regular 328 besides the engine, had a top speed of 253 km/h and could accelerate from 0-100 km/h in 6.3 seconds. Production between 1986 and 1989 resulted in 308 GTB Turbos and 828 GTS Turbos being made.