Two part question

[focushere]

I have a 2011 Mini Cooper Clubman S. Bad throttle lag. Can any upgrades fix this and still pass emissions testing? Also while accelerating hard getting on Highway the car started bucking as if fuel was being cut off. Happened in less than three seconds, but was un-nerving. Any ideas? Hasn't happened since. The car has 4,000 miles on it.

[vetteburna]

You should look into a TPS sensor. Something similar happened to a friends miata.

[bad venge]

I'd take it in for a reflash with 4k its in warranty, there was a computer upgrade they might help

[Byronics]

probable intake valves are cokeing up, take to dealer and have them run the test plan, clean intake valves with media blaster, possible what is wrong with your issue