Parts and advice
Nice shark nose!!
For parts, if you need interior or exterior depending on where youre located I would try a Pick-N-Pull... You cant beat their prices on large body panels or interior parts like dash boards seats etc... AND YOU CAN GET LUCKY, and find an L6 or M635, or a few Euro E24's out there with ///M options and sports seats, rear spoilers etc.
You have to be handy with the spanners and other tools, but its only 2 dollars to enter the yard and you can pull all the parts you desire...
As for your power steering leak that is VERY common, it is either going to be the High Pressure hose coming from the PS gearbox OR hose coming from the Res, either way you will notice cracking and ATF coming from the hose..
As for Brand new mechanical parts, all of the above vendors are great + try ebay, and Europarts.com!
Cruise control can be one of 3 things, comfort Relay, Fuse, or Bad stalk (cruise control module switch). Start with the quick and easy checks first, like fuses, then relay, and then move towards the switch.
Hope this helps