i have that same jackson racing kit on my 2.0 mondeo zetec, its very good indeed.

you dont need to upgrade the pistons, its designed as a bolt-on upgrade.

the PCM reflash is the american remap method they use on alot of motors, its not compatible with ours, so you have to get your own mapping done (i got unichip on mine, cost around £400 including fitting and mapping on a dyno)

if you fit it with induction kit and decent exhaust you will see about 200bhp (flywheel) on a 2.0 zetec. the standard clutch is OK for about 210bhp ish, so you would be OK.

i went one step further and fitted better cams & gears, different SC pulleys (for more boost), huge cone filter, water/methanol injection, big throttle body & MAF/injectors etc and now its up to 230bhp so i got an uprated clutch (i run nitrous on top)

it is a very reliable supercharger kit, very good MPG and emissions, excellent sound etc.

the down side is that its only a small blower, and has no intercooler (and no way of fitting one) so the max power you could ever get with it (without nitrous) is about 250bhp (with all the other bolt-on mods and headwork)

if you go to www.importcarpartsplus.com and email justin, he will probably beat that price for you