Been thinking about getting exhaust cutouts for a while now, after shipping etc here to England it's going to be quite expensive to get the electronic ones so thinking of just getting manual ones, anyone used the manual ones ? I'm a bit concerned about leaks or are they quite good at sealing ? The ones my local parts place has are these, see link, scroll down to S9/14 , also is there any amount of time they should not be opened up for when driving or is it ok to have them open all the time if I wanted ? Thanks

http://www.realsteel.co.uk/section9.pdf