curtis sparks timing advance

[supernatural]

how much of a difference does the timing advance from sparks make on a 400ex? can i use it with a cam if i go with one in the future or do i have to change it back? difficult to install?

[81 clark racing]

great throttle response and low end gain. best 20 bucks i ever spent! also very easy to install. you will need new side cover gasket. and no you can leave it in as long as you still run stock comp and bore