These are far from laggy, i had exactly the same on my 25 and yeah of course they are going to be slower to build boost than stock turbo but so is anything that makes decent power. But i would never call it 'laggy'. Anyone who does needs to try putting a gt30 on This is in my opinion one of the best comprimises between power, response and cost ($) for a street driven skyline. Im even considering buying it as it was so perfect on my car but no cash till end of the year