If you're au fait with the whole import scene, it seems that you'll be able to get hold of Project Gotham Racing 4 ahead of its PAL release, because the game is region free. According to Play-Asia.com, the Asian version of Bizarre's final instalment in the Gotham series will work with all three territorial versions (PAL, NTSC-U and NTSC-J) of the 360, and better still, actually has the Asian version in stock.
Although 360Gamer are not able to validate this claim at the moment they point out that Play-Asia's usually pretty reliable when it comes to such matters. Better still, with it being the Asian version, it's considerably cheaper (£25, sans tax and import duty) than the official PAL release will be as well – so not only does that mean you can probably get hold of Gotham 4 earlier, you could wind up saving a bit of cash, too.