lateral shift of the seats

[sb01box]

Hello,
I have a 01 Boxster 5spd as my daily drive. Have had it for 4 years now.
I have noticed gradual shifting or tilting of the seat towards the center.
When I purchased it the driver's seat would tuck into the rollbar opening with just a tad difference in the spacing between the head rest to the bar. Namely the space between the inside edge of the headrest to the roll bar was little less than the space between the door side of the headrest to the roll bar.
Now, I can not recline the back of the seat. the head rest and the roll bar are now touching. Looking at the driver's seat through the window, the seat is touching the roll bar on the left side.
swapped out the shift lever with 987 assembly, otherwise it is stock. picture below
any thoughts?
thanks in advance

[Keith Newby]

It looks as if it's time to pull the seat out of the car and check the mounting hardware. Does it move forward and back without issue?

[sb01box]

Yes, seat has no problem in motion. it is motorized and smooth.
no sign of wiggling or being loose.
is there a wear piece in the seat track??

my fear is that the entire pan is sagging in the middle.