Short shifter does not add hp but will help out in 1/4 mile time. With i/h/e, I'd say between 15 & 30 hp. It also depends on if you get a cai or sri, a rh or shorty, and if cat is eliminated or switched to h/f.
i dunno intake/headers/exhaust prolly 15-25 hp depending on brand and what not... i dun really recommend dc sports coz of all the shit i hear about them being crap... but i dooooooooo recommend comptech.. dude their race headers are great but they wont pass emissions
not really sure but prolly somewhere in the same numbers as the horsepower gains... prolly slighty less coz torque seems to be something harder to achieve than hp...
• Controls torque, diminishes wheel hop and improves manual transmission shifting.
• A must to use with modified motors and if you're heavy footed!
• Protects your existing O.E.M. rubber mounts from tearing.
• Even works with torn O.E.M. mounts.
• Can be removed later for stock running, if so desired.
• Installs in just 5 to 10 minutes on Accords and Civics!
• Durable HYPER-FLEX™ performance polyurethane construction.
Here are the negatives...
1) More engine vibrations, but u will not notice it with time.
2) U want to redline and drop your clutch much sooner than before, causing faster clutch wear?...
3) I can't think of anything more... Just get it...