most difficult cars, alarm/remote start

I prefer the easy ones too!

yes sir

From my side of the pond, Late 80's 5 Seires BMWs where you had to go the rear end for lock, deadlock close door and trunk contacts. Smart Coupe any post 2005 Audi or Mercedes the so called CAN specific systems from a certain company just don't work properly, Lotus Elise, same reason as Smart Coupe, I think it was a Pontiac for a while, stand them upright on their tails and you could work them, I've not done the latest BMW's but warning, to change the subject, if any one is doing Parrot kits or similar in cars with the latest sqare Euro-plugs, called MOST or quadlock, don't use the adaptor leads, they chop and change, BMW changed in 2005, use an earlier adaptor and you've lost the radio tuner, the only 8 leads standard to all are the speaker outlets. If it mutes, chop and insert the front speaker connections from the kit, if it doesn't do all 4.  

Easiest, 90's Japanese.

Can't do US except Mustangs, ain't done the course.

Howie..... always a wealth of information.

Ya know, the ONLY Bimmer I ever worked on is still working fine. I guess I was scared for no reason!

Gary,  don't you ever sleep? Mind you I was watching Die Hard 4.0 and I'm so anal that when Bruce Willis was attempting to hot wire a late 5 series, the reason he failed was that the colours were all wrong! Someone phoned me and asked what she could do in future because her E class was stolen whilst she left her key in the car with engine running, whilst posting a letter. I said short of Blackjax, she should kick herself up the back passage every time she left the car with the key in it.

You lot should thank your lucky stars you do't get French cars, Italians or Protons from Malaysia (3 gen old Mits, think Lancer or Colts from the early '90s)  Take Peugeots, don't use colour codes, just tiny writing on the wire, change colours every few months, 2 x ign1's, join them wrong way round on a remote start (either will work for immobilisation) and you've lost the facility to hit the footbrake to exit auto-start mode!  Radio is linked to engine management and to avoid all sorts of problems you wire acc from new radio to hard acc at ign sw or fusebox. The others just fall-apart, eg switches or trims when you work on them, panels don't go back properly when you put them backas in  Fiat and Alfa, you had to pull half of the wing (fender) off a Fiat Coupe to get through to the engine bay etc etc, Peugeots, dome light front, purple = 12v+, grey = door contact;  hatch grey = 12v+, purple = hatch contact!Peugeot vans, load area light is switched from driver's door( NB the colour even changes between light unit and switch contact)!  New Audis all CAN and everything hard to get at, think ign switch wiring or steering column cowl on Mk IV Golf/Jetta, the smaller Polo and the Transporter van use a multiplex lock and window close via a 1k resistor, the bigger cars use low current neg.!Also need separate door contacts AND diode blocking on most 'cause of the bloody Siemens body management every EU car uses.

"Someone phoned me and asked what she could do in future because her E class was stolen whilst she left her key in the car with engine running"

LOL howie. Yeah shutting the car off and taking the keys with you is always a good preventative measure.

Side note, Puegeots and Freightliners must be made by the same ppl. Was putting a phone in one the other day and the best part of that day was scaring the hell out of my coworkers with the air horn. Every wire the same color, and no easy writing either 2305 might mean ignition to whoever builds them but to me its just the time i got off work that night after taking my multimeter to EVERY single wire in the vehicle.

SIDE NOTE: When working on big trucks not all "wires" are wires. Fortunately I remembered that instead of multitesting an air hose.

ANYWAY... on with thee reason for the topic, lol.

5 - DODGE Why: I hate resistor/relay wiring.

4 - DODGE - Why: The ECM on the bottom of the engine but on top of the oil pan where you can only see it laying on the floor but lose sight the moment you put your arms up to reach it is a horrible place for tach wires on deisels.

3 - Id like to say dodge again out of spite but probably  FORD Why: like dodges but not as bad

2 - HEATED SEATS wiring before controlled by data. Why: Wires through door boots is crap and soldering to contacts on an expensive control board makes me nervous.

1 - RANDOM VEHICLES I havent done before Why: Just the lack of familiarity. Not necessarily hard but they take longer because you have to take more time figuring all the quirks and where the screws and clips are.