Too much weight reduction?

[HKSZ]

Try running lower psi in the tyres

[jmortensen]

I'd bet its an alignment issue. Unfortunately there aren't many adjustments to make on a stock S130. It's not a weight issue though. You just can't make them light enough for that to be a huge issue.

[sblake01]

I also doubt it's a weight issue. None of the stuff removed from the car was from the rear based on the opening post. What brand are your tires?

[bigoak]

Scientific assessment.

Just for fun (or to clean up the floor) I went into the garage and pushed around my 240Z, my 280Z and my Z31...assuming your 280ZX still falls between the 280Z and the Z31...the 240Z is way, way lighter...

[KDMatt]

My '76 gives me some hell in the rain every now and then. If I juice the throttle any more than a 'reasonable' or 'sensible' amount it'll spin and/or slide...

... but sometimes it's fun to drift around a corner in the rain... it can also be very scary when you nearly hit a BMW M5... yikes!