There is an easy installable and affordable ignition coil (IG) upgrade for VFR400R (NC30), RVF400 (NC35). You don’t have to buy expensive Nology ProFilre. You can install genuine Honda enhanced ignition coil which is MP10 at almost half the price of Nology.
The parts number is 30510-MCC-003 and no modification needed to install (only adjust the wire length). Just plug and play.
In 2006, MP10 is installed on CB400SF for minor upgrade. Japanese press release (http://www.honda.co.jp/news/2006/2060320-cb400sf.html) says that installed bigger IG to supply more stable spark and particularly improves the ease of handling in the low RPM. I’ve installed it on my NC35 and got the same result as Honda press release says.
NC30 and NC35 is more than 20 years old bikes so preinstalled IG (MP08) would have already deteriorated. I’ll recommend to install MP-10 for all users who own NC30/35 and have never been replaced IG.