i had a Krups 4020, they are ok with unpressurised baskets when temp surfing is learnt.
2] with milk frothing only do it without the attachment and i also removed the o-ring, just need a bit of an angle on your jug.
3] i loctited my screw in the group head, check its tight
4] try not to over tamp or grind to fine, i also found you cant rush it. after heating has completed turn the switch back to middle wait until it has finished cycling then switch it over to brew setting.
to help with steaming milk, after brewing switch it back to middle to cycle and then back to reheat water once heating light goes off then bleed off water when switch to steam and once bled turn back only a little bit until steam stops. then put your milk under and turn to steam.
hope this helps, Azz