It's not what you think.
I took my seats to Happy Ho's Upholstery in Langley to have my black cloth 91-93 driver seat repaired. The foam in the side and bottom bolsters had broken down like most LHD MR2 driver seats have. The side bolster had what felt like a cord just underneath the outside fabric. What it actually is is the foam lining having deteriorated over time and rolling itself into sorta like a string or cord... and that's what you feel on the outside. The bottom bolster form just breaks down and needs to be replaced. I also had the seat bottom relined to make it firm again.
I'm pretty happy with his work after I told him I wanted this seat to look like factory new. This place is a good option if you can't make it out to Ambassador in Burnaby.
Happy Ho's Upholstery Ltd.
Jong Ho - owner
#101-20058 Industrial Avenue,
Langley, BC
604-532-8923
Crappy pics... they look alot better in person.