One problem with the Mini autobox is that 1st gear is pretty tall and the stall speed of the torque converter can't be increased much above stock.
At least, the local converter gurus here in Sydney can't, they have done a few for Greig Malaure's GF's 1430 `matic.
For a 998 auto, the stall speed is only 1400-1500 rpm. I don't have factory figures for the 1275, but I believe it's around 1800 rpm. Same converter.
This low stall speed makes it hard to utilise the extra power available in a tuned A series, whether it's via engine mods or a hairdryer- low speed engine torque is usually worse than a stocker.
So- it's fine once on the move, but launches are not ... `brisk'.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
