California DTC - California My 2012

If I understand your first question, the update to the 1st generation Cali, the so-called Cali30, has 30 more horsepower and weighs 30 less kg.
I think the Cali30 came on the market in the 2012-3 time frame...T

 

Novitec makes a piggyback system for your Cali. It adds about 25 hp. For removing the drone, add the Capristo X pipe but keep the exhaust stock otherwise.
The x pipe really smooths out the sound and removes that annoying hum there is when the flaps are closed. The x pipe will also add a tiny bit of power.

But here's the deal. Adding 30 hp will not make your car perform like a Cali 30. The most significant reason for this, does not lie in the extra 30 hp or 30 kg less. That's actually not that big in the grand scheme of things. I suspect that there are heavier Cali 30 cars out there compared to original Calis. Options can make a big difference, and a chubby 110 kg driver will add 38 kg over my 72 kg.
What really makes a huge difference is the fact that they changed the gear ratios of the Cali 30.
If you really want to feel a change, add the Novi box and x pipe, but also add some properly light wheels, namely the HRE R101 Lightweight. Stick to the OE wheel diameter and rim width. Larger wheels will only add weight and act as an even longer final drive ratio, and that is the completely opposite of what you want to improve performance. The OE Cali wheels are real anchors when it comes to weight. Lightweight wheels will make a noticable difference.

 

No I highly doubt you cannot cure the droning by doing that. In fact, you might make it worse.