the MTECH H3 yellows in ecelica are X4 i think...(they were X4 when i bought them...did Isaac change back to X2??)
the Golden Yellows H3 only come in 4x
I currently have 4x installed all the way around for the past few months, the brightness is much further and I've checked my wires and always check the temperatures - they run at pretty much the same temp as the stock lighting.
2x runs cooler than stock - 4x runs at about the same as stock.
2x is bright and is a significant upgrade to stock... 4x is the same brightness as 2x except that it shines for a much further distance