Split cargo door is not a costly solution. It's very common on cargo vans - even the small ones like VW Caddy, Citroen Berlingo, Renault Kangoo etc. It's more - or - less cargo van solution so not used on passanger cars (also due worse reverse visisbilty). But MINI wants to be different.

Suicide doors have safety issues - and has to be approved by traffic agencies. And that takes some time. Also the torsional stiffness is the problem because there is no B-pillar so other parts have to be enforced (adding weight!). So the development costs are usually higher.

But BMW Group share their know-how among the brands: so the know-how from RR was used in MINI & BMW, also using some innovative lightweight & body enforcement solutions. Mind that BMW have developed RR Phantom & Corniche suicide doors, and considered & tested sucide doors for V5, X6 & 4dr 6er. So there is a lot of know-how available. Like in iDrive case. Have I mentioned new MINI is coming with MINiDrive?