??? For street driving (which like, what, 99% of people who own Fiesta ST's primarily do), low/mid range is exactly where you want power/torque gains. I like this. I definitely want more torque down low.
You have to understand how a small displacement turbo car works and how that is represented on a dyno graph. You will never see that power in normal driving, or ever really while driving "fast". To represent those gains on a dyno the car must be under full load from low rpm, so the car is in 4th gear at 1500-2000rpm and the throttle is fully opened. The load the dyno adds would be similar to doing this on the road. You will never be going WOT on the road at 1500rpm, or even 2000rpm in 4th gear. If you did, you have no expectation of going quickly, because if you wanted acceleration you would downshift to take advantage of gearing. It takes time to build boost, so if you were to go WOT in 2nd gear on the road from 2500rpm you wouldn't get full power until 33-3500rpm because the revs are increasing so quickly and boost has to build. So in this situation you are only seeing a small benefit, but within a second or two you are in a region where the power losses show and the car loses acceleration. This prompts a short shift (because you can feel the larger power drop when torque is falling so drastically) and you end up in a higher gear where you lose the multiplication of torque that lower gearing provides. The "feel" might he there, but it doesn't translate into a large measurable improvement in normal driving.
I would prefer to see parts that leave the low end as is and only increase torque from 4000up as each lb ft is worth more hp the higher you rev and you don't waste it on wheel spin, cooling requirements etc...