The Top Gear time for Lotus was set in the wet, so it just beat a wet Lotus with the SS kit fitted.
Many FWD cars are fitted with LSD, in fact fastest production FWD around Nurburgring the Renault Meagane R26R has one, as do the R26 F1 and Cup versions, and new Civic Type R in Ltd Ed Chamionship White will have a LSD said to make it much better than standard.
Of course the integra Type R DC2 (meant to be best FWD car ever) & DC5, original JDM EK9 Civic Type R, the JDM EP3 Civic Type R has LSD, and the new JDM Civic Type R FD2 including the radical Mugen Type RR all have LSD's.
New Ford Focus RS is said to have one as well.
You can buy the Alfa Q2 diff for about £300, it's dam good value, and I am sure I read somewhere that the reason the Abarth Models of GP and 500 use an Alfa 5 speed box as opposed to the 6 speed FIRE box as it can't sustain the power on durability testing.
But considering the MiTo is near enough same car as 500 Abarth and its said to have electronic tricker at play and no mechanical diff, sure 500 will be similar.
Most cars now by employing Bosch electronics have very similar setups.