Sarto

The standard S4 1.6 Spider lacks the alloy wheels and larger section tyres of the 2.0 model and the trim is more basic using plastic in place of leather/alcantara trim.
Check for corrosion on any S4 along the sills, behind the body mouldings and under the nose. Spare wheel well often rusts out if the boot seal is perished and check the footwells, front and rear for dampness.
Engine should be good with regular maintainence for 100k miles. They are very hard to source used.
Transmission should be light and precise but don't be put off by a few rumbles or vibration from the propshaft. This is easily corrected with new bearings.
Check all the electrics work, windows and mirrors often fail but are usually just bad connections/earths.
Get out and enjoy the summer in your yellow Spider and remember Spiders are NEVER driven with the roof up!