Do a LEAKDOWN test!!! don't pull your motor apart
White smoke is coolant.
Check your MAF wiring, and your Grounds.
My RB did the same thing with my bad harness.
It would run roughly with or without the MAF.
I'm not sure why you have smoke, but the MAF issue seems to be wiring
Could you explain to me how bigger tires in front will cause understeer?
By bigger do you mean wider or taller?
Taller I get more sidewall and roll over, but wider?????
If you have the $$ just switch it up to a one piece aluminum shaft $350.
had a speed dependent knocking under the car when mine went bad.
P.s. change the rear trans seal while your at it.
I don't know if the spline on an SR NA Tranny is the same on a Turbo but if it is just buy a used det flywheel and resurface then get a details clutch. Just make sure the flywheel will clear the bell housing and everything else.
If you have a safc then break out the wideband and play with it and just don't boost.
If not then just keep checking. Your oil and wait till you get a tune.
It's the headlight switch.
I SEARCHED it a while ago.
I have the same problem except my low beams work and my high beams only 1 works.
Changed the headlights too.
I have Adjustable KYB AGX and Eibach Pro-Kit springs with brand new Nissan Strut mounts & Bushings.
They have about 4 or 5,000 miles on them.
Just came back from the Tail of the Dragon and I was very impressed with the car.
Handled awesome and still has civility on the crappier roads...