Delphi coils are better than the Bosch ones IMO. Cheap and easy fix. Plugs are also on Amazon with the Delphi coils. I replaced both coils and plugs and my car runs like new again.
Walmart for the AC fluid. It's the same thing as air in the can that one would use to de-dust a computer keyboard. Buy the can with the pressure gauge so you can see the pressure you're putting into the system. I did mine when the AC was blowing less than cold. Fixed it easily.
And pay for a PPI from a local and trusted indy. $200 spent is always cheaper than $4000 in repairs. And buy a car from an owner who knows BMWs. Otherwise get a big discount for your troubles.
GL. These are great cars. I've owned 7 BMWs since 2001 (E46's, X5, X3, E93)
2001 330i Sport 5spman- Sold 48k miles
2003 X5 3.0i Sport 5spman- Sold 146k miles
2001 330ci Sport 5spman- totaled 140k (thanks, son)
2001 325i Sport 5spman- fixer Sold 164k miles
2008 335i Conv 6spman - Sold 112k miles
2005 330i ZHP 6spman- Sold as totaled 110k (thank, son)
2013 X3 35i Msport (bought Jan 2016)
2003 330ci Slicktop Sport 5spman w78k (bought Mar 2017)
2012 335is E93 DCT 34k (bought Jul 2017) 53k as of 20191211
2003 330ci Sport 5spman 32k on it (Oct 2018)