Had the car 3 months and already 3 times have had to be towed to a garage with "Anti Pollution Fault". Paid so far £450 in repairs and computer checks on that fault alone. Do not trust the car at all to run.
Also electrics seem to have a gremlin.
Alarm warning light has been on since day of purchase.
The horn doesn't work.
The electric passenger window only operates downwards from the drivers side.
The CD interchanger has chewed CDs and now refuses to work at all.
The radio regularly wipes out all the preset channels
The wing mirrors have often refused to pop out on starting ignition.
Also seem to have real trouble with getting wheels to stay balanced after 3 trips to Kwik Fit & the like for balancing (vibrates at 70 miles an hour).
Wish I'd stuck with my 8 year old Seat. At least it never gave me any high expectations and ran solidly during it's life with me.
Bought an 2002 307 xsi in may 2005,just about every problem you have described I have also had, bad vibration over 70 miles an hour even after wheels re balanced. Anti pollution warning light been fixed twice, they said it was a dirty sensor switch. Car going in next week again same problem, but now centre screen flashing up everything at the same time. When you drive the car you have to listen to the warning bongs going off every couple of seconds. Bad fuel consumption, low thirties on a run. Do not think I will have the car for too much longer. Shame because the car looks great and have no complaints with leather interior, very comfortable. Sorry, but I think 307 a bit of a lame duck.