Good question. There was a software tune, free flow exhaust, high flow air intakes, clutch, flywheel, engine brace, and suspension. There are 3 tiers. This was entry level Dinan modifications. Dinan s3 in its day was a $40k outlay - and supercharged out to 600 plus bhp. Apparently they were numbered and there were 30–40 made to that spec.
For me personally, my modifications are relatively minor, and can be can be changed back pretty simply. Not sure whether performance is hugely different today. I didn’t buy the car for the Dinan status- I loved the colour, and the condition and price befitted my criteria! ?