A few questions about the artificer 3.5 D&D

[ShadowfireOmega]

Ok, so my questions both involve the Metamagic Spell Trigger class ability the artificer has. My first question is can they use multiple feats at once for the combined cost, or just one? Number two is is there a limit to how many levels you can up it by with Heighten Spell? For that matter, is there a limit to how high you can make it with metamagic item using Heighten Spell?

[phlidwsn]

Spell trigger I believe was erratta'd to be a single metamagic applied only. You can use invocations to apply a 2nd though.

[ShadowfireOmega]

No idea about restrictions (if any) on Heighten?

[Deophaun]

No idea about restrictions (if any) on Heighten?
Just the normal restriction:

A heightened spell has a higher spell level than normal (up to a maximum of 9th level).