We test drove the X1 (in 2wd form) and the E91 (2wd) - both 2.0L diesel, both in many ways, the same.
The height of the X1 will mean that the 320 or E91 will be the better in a corner than a taller X1 but our decision to get an X1 was down to access for passengers - the height of the X1 just made it easier for our needs.
As for a 2.8 or 3.0 AWD E91 in itself....... I just wish they sold it in the UK!
318i E36, 320i E36 Touring, 530DSE E39, 525DSE E60,
325i Sport E46, 318Ci Convertible E46, Now in an X1 sDrive20d SE E84