02 1.6 focus lacks power

I just bought a 02 1.6 petrol focus with just under 80k miles a boy racer had it and has lowered it and put in a induction kit

when I was driving it home I noticed it lacks power on hills ( no extra revs just loses power) it also does this when trying to overtake but not as bad and it slowly builds its speed up I have got it over a pit ready to be given a oil and filter change and replace the fuel filter but noticed there is a split in the exhaust on the flex just after the exaust manifolds I am gonna fix it when I service it but was wondering if the lack of power could be caused by anything else as I am having to book the day off work to service it as I work 7 days a week at the moment I have looked at the plugs and leads but they all look quite new any advise or suggestions would be great many thanks Wilky