SH's harder to mod?

I heard that SH's were harder to mod and my question is what is it that is harder to mod in the SH? exhaust? suspension? Also, because of the extra weight of the ATTS system do SH's have a slower 0-60 than a base? Thanks in advance for the help.

Its not so much that they're hard to mod, its that its hard to find parts for it.

The weight difference between the Base and the SH is negligible.

What parts are harder to find for the SH?

Mostly exhaust components; Header and Catback in particular.

Why are they so much harded to find and what is the difference?

I think because the ATTS unit is housed underneath the car.

i think it also makes an engine replacement harder if you blow your original h22. the location of the oil filter is different if i remember correctly