Hi all sorry for late cause suffering from fever.
First i want to tell u all that platinum or Iridium plugs uses on high spec engines like turbo or super charged cause of extreme cumbusion,temp & high rpm, on normal engine u can use but it give u only good service life, otherwise its heavy on pocket,if desire for it NGK Gpower series is very good option for all, producing 4 tip plugs also equal in service life like platinum cause of carbon fouling which is in CNG, in smaller vehicals use orignal number or can be 4 tip, Bosch also produce 2 or 4 tip platinum plugs but these are not avail in market if avail these r too expensive check web site www.boschautoparts.com
@picco,
W20EP-11 is orignal number for lancer, in NGK platinum BKR6E-11 or Bosch 4tip.
like Alto F10A CNG in 4tip Bosch 503 WR78 or normal w16exu rec.
@cargeek,
W16exu is recommended for 82 corolla.
@redsony
Denso IK16 is usefull for 1.8 1ZZFE but its expensive price above RS3000,u can install Bosch 4tip FR78X is light on ur pocket & equallant performer.
@Toyo,
for ur 660cc suzuki i recommand u Bosch YR7DC or very best Denso XU22 EPRU.