The B46 is probably less prone to various leaks than the N52 and it’s more powerful. It’s proving to be a pretty reliable motor. Pricing. Buying now then swapping later. It’s hard to say. Just watched a pretty interesting video on this forum yesterday. Used car dealer analyzing CarMax and where the market is headed. His prediction is that prices are headed down substantially and waiting to buy is the better choice. 330i prices have come down. They’re not super unreasonable. If this dealer is correct I think the odds of a 330i you buy now dropping in value more than an 840i GC value drops are pretty high. So, the price difference between the two will be wider than it is right now. If that’s much of a concern for you then you could find yourself with a 330i that you can’t sell for enough to get into the 840i GC. Just my thoughts. Take ‘em for what they’re worth.
https://g20.bimmerpost.com/forums/sh....php?t=1990419
Having said all that - his video gives me some pause, but I want a 2020 pre-mild hybrid M340i and I think the same thing is going to happen to my 2018 F30 340i M Sport; I think the value of my 2018 is going to decline more rapidly than the M340i, so I’m making the swap now, while my car has more value.