boost is addictive. and thats what the fswerks doesnt really support because it uses the stock zetec exhaust manifold. its a great kit, but you'll max it between 250 and 300whp due to flow limitations with that manifold depending on the turbo you choose (id say gt2871 or 28rs).
toms kit is good too.
and top speeds is great if you want to shoot for 400+ whp.