Rest assured your english is better than my spanish!!
Are you saying that 30% power hike is all you want ?, if so you can get easily more than that with hidden mods, and still get through tthe technical test, head and cam work, work really well on these.
If you want to go turbo route it seems a shame to peg it at 30% more power or is this the law or something in spain ?
If it is (the law) you can always have a switch to change between 30% and 100-200%, or you can remap etc for nice clean emmsions.
tabetha