new boy needs help

[wagon]

new one needs help just got the garage to remove my coil packs for me and see if there were ok due to car back fireing from exhaust and the induction kit when the boost comes on at half bar then after a second she just goes the coils were ok but my spark plugs are brown due heat the garage said the plugs have been in the car for about 7 weeks ngk plugs the garage said it looks like it is runing very hot i had these plugs in my legacy turbo no props. any you boys got any ideas any info will be helpfull it is a 96 wagon turbo uk