Dont listen to the scare tactics of the idiots who know nothing.Just make sure you take it to a place that knows what they are doing and have years of experience. I run a series 7 celica 1.8 T-Sport with NOS the celica has variable valve timing similar to the Honda. A 50 bhp shot of NOS should need no other alterations to timing or anything. Should you want above 50bhp then you need to start messing with timing and uprating the engine. DO NOT FIT A NOS KIT YOURSELF unless of course you want melted pistons.PS: ive been running NOS in my celica for 2 years and not had a bit of trouble with it.