The 3M mat the last i knew could be got from Bukit Batok
(apologies that I do not have the address anymore), apparently the
shop does a custom cut for you...good deal
I am
using Korean mats, which are exactly identical to 3M (thickness n
softness), cut to size with velcro on the bottom. These were given
FOC by my SE.
For Audio stuffs, 2nd stuffs, you may visit the links provided by
our forumer in the earlier posts, else a good place would be sim
lim square, but you will have to DIY or have it fitted by some
installer. I do not think an upgrade of the Audio system would void
the entire vehicle warranty, but probably on the Audio section
only. I have changed my front speakers to CDT HD62, disabled my
rear speakers, carried over my Pioneer HU and JL Audio 12" Sub from
my previous ride.