Trying to get in the 13's

[dane75]

My First effort in my BF XR6 NA at Heathcote was 15.3190 @ 95.36 - the car had extractors, 2.5" catback and a cold air intake but only the standard tune.

Today the best I could manage was 14.624 @ 99.01 - this is after changing to 3.73 diff gears, 20% Underdrive and a Tune.

I'd like to try and break into the 13's, does the difference now come from trying to get more power, shedding more weight, better technique (I'm pretty green with it all) or a combination of all 3. Any advice people may have would be appreciated.