I'm not haranging you, I'm just advising you. On something like a Datsun, that's a really good idea. However the problem with Corolla's is the aforesaid mentioned lack of space. When I fitted my Webers, there was exactly 38mm between the carb and the tower. I don't know the measurement on a 30, but I think you maybe struggling to fit 4 inch (100mm) K&N's on, due to the slant and the tower. Remember that although you can have the trumpets, you still have to be able to get the filters on and off for cleaning. I sincerely hope you can fit K&N's, as they're an excellent filter, however if you want trumpets, you may have to go socks, due to fitment problems. Nor am I slagging the gentleman who gave you the advice, as it's sound advise. I'm just suggesting that he may not know the space issues involved.
FWIW I have 40mm sandwich filters on the 3K, with no trumpets, and socks and small trumpets on the 2TG.