bro,
1. the TRC off/on button should be below the stereo system, next to the open slot...... the red button is for shift release......
2. try to feel the bumper inside...... if the bumper is having some feel like "fibre sheet" or rough surface, most probably its a fibre version... original ones should be able to tolerate some flex towards the bumper.... as for the black middle part, maybe it has been repainted....
3. E46? hahahah.............. u must be joking.......its a personal preference anyway....if u prefer everyone (literally) oogling at ur ride when u pass by some cafe/mamak, then altezza is ur choice (show off!!!- hahahah)
for normal parts such as filters and so forth, its rather easily available...... but for special parts such as drive shafts and body parts, its kinda rare....... normal wear and tear items such as brake pads are readily available.......
common used springs? not sure......but there are members running on tanabe, trd and so forth....... for an 18 with lowered springs, i dont think its a problem........ probably clipguy can give his comment on this.........
anyway, i have a set of tanabe springs for sale.......PM me for more info...... great handling and ur car looked stunning after installed........kekekek