Turn 10's Dan Greenawalt would tell you there's absolutely no rivalry between Forza and Sony's Gran Turismo, but he'd be telling fibs.
Forza and GT are in the middle of a war fought on forums and fansites across the world - physics models as weapons, car lists and tracks as armies, AI and online modes as battlegrounds - and it's a war Forza won two years ago with Forza 3.
The first two Forza releases fell short of Polyphony's benchmark Gran Turismo 4, but Turn 10 built three games in the time to took for Polyphony to make one. By the time they made it to Forza 3 they had changed everything in a way Gran Turismo 5 never did.
Forza lost a battle or two along the way, of course. Gran Turismo 5 fans would point to Polyphony's higher polygon car models, 16 cars on track, night racing, and 500 more cars in its garage than Forza 3. Forza players would point out only 200 of GT5's 1,000 cars were new HD models and that almost half Polyphony's total is composed of Nissans, Toyotas, and Hondas.
Forza players got custom liveries and an unrivalled online marketplace but Gran Turismo players had sixteen cars on the track. Gran Turismo 5 got a 3D mode while Forza got proper online matchmaking. Gran Turismo 5 had the Top Gear Test Track but Forza 3 had better tracks and career mode, full stop.
Gran Turismo players had the ridiculous B-Spec management mode for mega-nerds while Forza focused on rewinds and assists for more casual players. Both sides claimed to have the superior handling model. Things got messy, but ultimately, Forza 3 won.
Polyphony's more traditional approach to game design lost out to Turn 10's obsession with The New, but the bloody noses dished out by the PS3's 16-car races, Top Gear licensing, and supposedly superior handling were noted, and Forza 4 is Turn 10's answer.
WHEELS OF FORTUNE
A car is a big metal box which meets the road in just four tiny places, so Forza's new handling model emphasises those rubbery points above everything. Turn 10's new partnership with Pirelli has given the studio a mountain of data on modern and vintage tyres, and the result is a sense of car-on-track contact like no other game.
Forza 4's cars really handle like cars, with every scrap of your real-world driving skill directly transferable to the game. Classic cars wear classic tyres, and new suspension modelling makes the feeling of contact even more tangible.
Turn 10's second big partnership aligns Forza and Top Gear in a multi-year deal and puts the Top Gear Test Track, the Kia C'eed, and Jeremy Clarkson's smug voice in the game (his digitised face, of course, could have made for a considerable dent in sales).
Clarkson chips in on the new Autovista mode, where you can view obscenely high-resolution versions of some of the cars and interact with them in a stack of ways. More than a glorified gallery, each car has to be unlocked in custom challenges, and has dozens of interactive points which only appear when the car is inspected in detail.
Each Clarkson voiceover is written by the man himself, meaning Turn 10 can lavish thousands of man hours on lovingly modelling a car, only for Clarkson to call it pish. But the real reason Autovista is exciting is its impact on the series' future. Autovista cars are millionpolygon models with new leather and carbon fibre shaders and a level of detail never before seen in a racing game.
Just rendering one of them in an empty garage makes the 360's graphics processor weep, so throwing 16 of them around a track is impossible - for now.