I am sure there have been threads before, I cannot find a good one. What can I do to improve the speed and performance of the CS for $5k or less. It is a normal CS, with 18" wheels. I have too many miles on it to get out of the loan so buying a CTT is not the answer I am looking for. Are there performance chips, a different exhaust, blower/filter kits , etc. Thanks.

 

Normally aspirated motors tend to resist performance increases, it's just their nature.
You could add chips, exhausts, filters, etc, but the actual performance increase vs the perceived performance increase might not be what you are expecting.
Forced induction is about the only way to get a signficant increase in HP out of the motor and I haven't seen a turbo/supercharger kit for a Cayenne, at least not that jumps to mind.
The usual players would be the place to start looking (in no particular order):
FVD, Gemballa, 9ff, Revo...etc.

There is also the suspension upgrades (lowering kit, coilovers, etc), along with brakes, wheels and tires.

$5K seems a bit on the low side IMHO, at least to get a decent return on investment.

 

Try here at Evo for a start.
http://www.evoms.com/marketplace/mar...C1FFF37A382%7D

ECU upgrade - HP 12-15 gains, TQ 12-15 gains $595
Cat Bypass Pipes - HP 17 gain $550 (save 15+ lbs. on the car too)
Evo Air Intakes - HP 10 -12, TQ gain 10-12 $595

Also look here for exhaust: http://www.cargraphic.de/index.php?/...esolution=1024
Cargraphic Exhaust - HP 10-12 gain (saves about 12lbs on car too)
CARP55SETS
Sport backbox stainless CAYENNE V8S
Super Sound Export-Version
Price: 1.495,00 EUR = $1896 USD
.........so for $3636 you will have a boost in speed ( more than perceived but not as much as you may "need". HP is not additive 12+12+17+15 = 56HP, it will be more like 30HP probably, only 15 maybe at the wheels?

But is is only about a $4700 investment (after shipping and having everything installed) so under your $5000 request.