Sluggish with the efi setup. Am going to update mine over the winter. Option1 upgrade engine to fiesta turbo spec,will need pistons ,turbo , intercooler and upgrade on ecu and wiring etc. Option 2 change to twin choke carb or twin carbs. Option 3 drop a cheap 1.8 or similar Zetec engine in. It's all about how much you want to spend,mk5 are not worth as much as 3&4 models so we will not get the money back, but I do agree with you that they need an upgrade just to keep up with modern day small cars.