mk3 golf gti start problem

hi all, please help! im having a mare with my 97 mk3 2lt 8v golf gti! 1st it wouldnt start when the engine got hot, was told 2 get new dizzy, got new 1 from ebay was told its the correct 1 4 my car (agg engine code) fitted it myself start problem solved but car running lumpy, no power. took 2 local mechanic who did timing, was running alot better but wouldn`t rev past 5000rpm, now car wont strat @ all! tried a different coil pack still wont start, anyone got any ideas please?
cheers