ok my xr2 is in dire need or a service !! engine feels rough as ya like

oilstems need replaying, exhaust is blowing, unresposive, doest like starting in the cold, an if i put my foot down to overtake etc it wil hold bk, an jerkl an then acclerate, so carb needs cleaning an all that, timeing as well maybe!! loads, byut its all being donw 2mora, ive also got a ashly manifold an full exhaust to fit along with filter, an 25mm lowering springs... so wondering how differnt it will feel as its all stadard at the mo!
thanx
Tubz