i wud go with the normal plugs jer ,and change often. unless ur engine makes it hard to access the plugs ie 6a12tt, den u need to go with the long lasting plugs like the iridiums
6A12NA and 6A12TT is similar, hard to access the plugs on the rear bank.
u hv to take out the intake manifold first, which requires alot of work.
which is why Iridium plugs are recommended, they can last 100K km.
if the engine is just 4 inline (like 4G63NA or 4G63T), then ok coz easy to get access to the plugs.
I purchased a modified Airtrex today and boy does it move!!
On my journey back it jerked a couple times when I planted my foot so it could be that its not the finished article just...