What makes this kite so slow? Can the bridle be modded for more speed?

Should probably list what year/generation imp you are referring to.

2, 3 or 4-line? ... Assuming the Quad?

ATB,
Sam

4 line 2008 or 2009.

Turning speed or flight speed?

Realize that this is essentially a beginner kite in the Ozone line so it's probably detuned a bit for first time pilots.

Is the speed something that has always been an issue or developed over time?

Do you have a lot of flight hours on the kite?

Is the sail coating still fairly crisp or has it softened quite a bit (porosity)?

You might also find this thread of interest: Ozone Imp Quatro Not Pointing So Well Anymore

ATB,
Sam

Slow kite is vague, describe how the kite is flying and how you would like to fly.

noticed Reactor and flows cover imp 4.5 wind range. sell imp to newbie to enjoy. just sayin

This is a friend of mines bigger kite. It's always been just a really slow flying kite with low buggy top speed. It just won't go.

The 3.5 Quatro was my first kite enjoyed it while honing buggy skills in small areas, it is a fore giving entry level kite not intended for speed runs.
if your friend wants to go faster must purchase a more advanced design kite.

Kazedoka probably right and you're probably trying to eke out Koenigsegg performance from a Chevy.

If you really feel like flogging the horse with mad scientist tendencies about the only thing I can think of is a DIY AoA adjuster to see is slight AoA adjustments yield modest performance gains.

The saner route is probably to go ahead and just upgrade the kite.

ATB,
Sam

I agree . This kite is designed to be low power. Messing with the bridle will be an education with very little reward. Shopping for a more aggressive kite seems best ?

If he wants to tweek I agree that an AOA kit would be the best way to go about it . That is if the kite cascades proper for splitting A.B.C. ?