Will bigger rims and lowered suspension effect PSM???
 

Hey,

I have a 01 Boxster S. Im interested in upgrading my wheels to 19 or 20" techarts and then lowering the car 1". I was wondering if this would have an affect in any way with the PSM?

Please let me know. Thanks.

I think you will be facing a multitude of issues PSM being the least of all:
The first problem will be ABS, I believe the new diameter must be within 3% of the old diameter, here is an online calculator: http://www.discounttire.com/dtcs/infoTireMath.dos I'd guess that the same rule of thumb will hold true for PSM

The next problem you will have somewhere I have read that 986 are officially only designed for 16" ~ 18" rims.
The larger the rim, the lower (stiffer) the sidewall and the suspension will have to absorb more bumps. maybe there are some members on this board with 986 and 19" rims.

I don't think that lowering the car will have any effect on ABS or PSM

And last not least: IMHO 20" rims don't look good on a 986, I think the sweet spot is with 18", maybe 19", but that's just my opinion...

With the proper tire size, and wheel upsize (no more than 3% stock tire diameter)you should have no problems even with an 1" drop...The 986 does not look good with 20s IMO.

Grizzly's been "cheating death" for years with 19s on his 986 (IIRC it's a 97, which isn't even supposed to run 18s).