Here's a list I found:
03-04 had the yellow in the lights. 05 had clear lights, also clear third brake light. 06-08 lights are clear.
03-04 had no reflectors on the front bumper. 05 had reflectors on bumper.
06-08 had reflectors on fender lip.
03 M-sport seats weren’t available as an option until around mid-2004.
03 did not have passenger window one touch operation.
03 did not have remote operation of soft top from the key. 04/04 build and newer did.
04/04-newer Euro spec Z4’s have the brake force display on the lights. U.S. spec Z4's since the beginning.
04/04-newer The sound generator was only available on the 3.0i/3.0si.
03-05 you will most likely want to replace Vanos seals. 06-08 seals made from different material non issue.
05 came with an MP3 capable CD player (it has a black surround).
05 had several updated parts. Water pump and steering issues fixed.
05 The 2.5 had a five speed manual and a six speed in the 3.0i. 06 that was changed to both 3.0i and 3.0si having six speed manuals. The automatics were changed to six speed as well in 2006. They were both five speed in 2005.
03-06 Tire pressure monitoring done by abs, 07-08 done differently (if you change rims you will need to add the monitors to the new rims).
06 The new engines were the first without dipsticks.
While the 3.0si produces more power at 265hp than the 3.0i in the 05 cars, the engine is also a lot lighter. So, you get more power and less weight. Also, the engine produces torque very lower in the rpm range.
You do not need to wind it up to high rpms to get lots of grunt.
06-08 Suspension modifications were made to make them ride better with run flat tires. They were reworked to be a less harsh ride.
06-08 Additionally, the headlights have been re-designed and now include corona light rings as standard on all cars specified with Xenon lamps.
06-08 Bigger front brakes. Bigger standard wheels 18" vs. 17". Sound absorbent material in the doors added, along with insulation on roof motor: Very important improvement from 2006 is the modified electric motor controlling the soft top. The old motors are not water proof and they will sooner or later break down. Very costly because you have to remove the whole soft top to repair it.
06-08 Heater control bezels, Changes to hood locking mechanism, Changes to electronics - brake drying, hill start assistant, etc.
06-08 you had the coupe available.
07-08 has 3 flash turn signals, and came with aux input adapter.
Cheers
Dice
:lol:
