Tune up time??

[Rob175]

Just looking for opinions on tune-ups. I have a 98' (non-S) 5 speed with 90,000 miles. The car is in very good condition, it's my summer sunny day driver and it gets driven about 5,000 miles a year and is stored inside during the Chicago winters. I'm not getting any CEL and the car starts and runs well and I'm getting about 27mpg. (btw, clutch is still very good too)

My "indi" Porsche shop has suggested I have a tune-up performed now that it has 90,000 miles (plugs, all coils, etc etc).....to the tune of about $1,200 (I'm not a wrencher)

Question......should I leave the car alone or spend the $$ for a tune-up. I'm thinking that as long as it runs well, perhaps I should just leave it alone? Also is $1,200 for a shop to tune it up reasonable?

Thanks