This pack contains the 1987 Xero P70, a mid-engined italian sports car, powered by a 3.5l biturbo V8 and making hp numbers in the high 400s, about 470. It hits nearly 300kph on paper and might hit them in a test. Also, it tends to oversteer a bit, witch makes it not faster, but more fun to drive.
3.5l V8 BiTurbo, about 470hp, over 500NM torque, rwd, 0.9 bar turbo pressure, medium tyres
The other variant is the P70RR, that has about 100hp more from its 3.8l V8 Biturbo with 1.1 bar pressure, semi slick tyres, more downforce and is wider.
Both cares seem really similar, but as of stupid design, the only parts they share directly are the frame and the whole underside/suspension stuff, the wireing, the badges, the taillights, most cockpit elements, but many are lightened for the RR... well and nearly every body piece is either made from a different (lighter) material, widened or slightly changed in shape for the RR, which made production costs really high.
Disclaimer: hp figures might be inaccurate, i forgot them...