Hi Paul, welcome from me in Hertfordshire, as regards your 2.8 and air filter you have lots to choose from, I started off with k&n which is oil impregnated but ended up with a dry gauze filter as in pic witch is cold air fed from just under rad, a heat shield is another good choice, as for performance gains I would say maybe a HP or two but nothing you'll really notice, to be honest with the S/S exhaust you may free up another couple, again not really noticeable,however if you then get a remap you'll be able to see just what gains over stock you've made but then you'll probably have lost some from stock anyway so gains are really minimal. The sound gains from both these mods are what I would consider worth while as the exhaust note will change plus the intake noise will be heard if stock filter deleted and replaced with cone. The 2.8 is a good engine with 193hp and 0-60 in just under 7sec and unless your willing to spend big bucks on it you'll only get small gains for your money. Don't spend big bucks unless you do your research thoroughly. There are turbo and super chargers out there which would put you in the realms of ZM speed and excelleration but on there own are dangerous, you'll have to upgrade all round handling /braking performance to match the new engine mod, so it's worth thinking of a ZM in the first place,this is imo only of cause, don't want to rain on your parade but I'm afraid that's how I see it. You can do a lot to enhance the handling and the looks of your 2.8 and remember it's no slouch any way. Come and join us at some of our meets with your Z I'm sure you'll enjoy it, Google luck. Rha, Roy.