What will happen if the vanos and the purge valve wires get switched on a 2000 528i BMW? My car won't start now... Are the the components fried? A fuse blown? Or the ECU now messed up?

Lots of guesswork here.
Firstly, have you checked for compression on all cylinders.
If compression is low or non exisistant then you have a major problem probably caused by the timing chain slipping and causing damage to the valves /pistons etc
I would do this first.
Roger

M54 is interference fit.

noise could be timing chain tattle due to tensioner failure, fault now sounds like valve timing wrong after changing vanos, there is special tools to set them up, also check the valvetronic servo motor. Scanning for fault codes will also be very useful

BMW, 3.0i has two Timing Chains. Primary Timing Chain can be
reached by removing the Harmonic Balancer. Lower Timing Case Cover. Vanos Adjusting Unit. Secondary timing chain replacement will require removal of several components and Vanos Adjusting Unit.

there is a special procedure that needs to be done with the DIS machine see BMW for initializing the vanos units

the most common oil leak on the m5 and m6 is the vanos high pressure line located on the front of the engine in fact this is the only area in which i have seen a leak on this car in the shop

Sounds like a VANOS problem. If you have $70.00 (American Dollars) and about 8 hours of time (at most) you can replace the VANOS seals. Here's a place to buy them:

http://www.beisansystems.com/

You might as well change the valve cover gasket as well since you have to take the valve cover off to access the VANOS.

Hope this helps!

will rsearch this at work for you and will get back after weekend

I had the same issue with my 2000 528i. You more than likely need to have the Vanos seals replaced. BMW will tell you that the Vanos unit needs to be replaced but the problem is more than likely isolated to the OEM seals that shipped with the Vanos. This issue has been reported by several BMW owners. This issue has been thoroughly documented and reported to BMW in an effort to seek a corrective fix. Since BMW failed to address the problem, the guys that investigated the issue started their own company providing superior Vanos seals to the deficient OEM Vanos seals.

The company is Beisan Systems, LLC. I ordered their Vanos seal kit and had them installed at a local BMW performance shop for less than half of what BMW wanted to charge me for a Vanos replacement with the same faulty seals. Besian also provides step-by-step DIY instructions; if you have the time.

http://www.beisansystems.com/index.html

Good Luck.

Your Vanos are shot. here's the link to Beisan Systems. They sell a DIY kit to repair the vanos. http://www.beisansystems.com/ or Dr. Vanos sells a rebuilt Vanos using the kit from Beisan Systems..... http://www.drvanos.com/ Either solution will address your issuel which one you choose is based on your mecahnical expertise...