Moderators: IMOC Moderators, IMOC Committee Members
Has anyone upgraded their ECUs and also installed bigger fuel jets and if so was there a noticeable difference in performance?(it makes as much power with the stock filter as without one at all!), change the exhaust manifold for a freer-flowing one, likewise with the exhaust as the OEM one is silly heavy. A'Pexi Power FC will give the best results if you're planning on engine remapping but is a bit overkill for an NA application: A regular E-Manage or Unichip will suffice, it's mainly down to the tuner. If you really want to make the most of the car then get some lightweight wheels on there, some Advan Neova tyres, a decent set of dampers and springs and as much chassis bracing as you can afford, the minimum being a front strut brace + TTE-style underbody X-brace. The mk3 is all about how the car handles as opposed to how quick it is in straight line, so play to it's strengths and you'll have a wonderfully balanced car. 
- much appreciated 
ekona wrote:
Solid performance increases have been proven both over here and in the US where PPE are based. PPE website The main cat is more than enough to cope with the emissions by itself after the engine is warm, and you're not removing that at all by changing the manifold or exhaust (as long as we're talking about cat-back exhausts or backboxes only). That said, PPE do make their own high-flow cat along with an exhaust and you'd be hard pushed to find better quality items than them. The best performance mod I ever made was swapping to an RPS lightweight flywheel: Strictly speaking, it won't gain you any power, but it will mean you'll lose less via the transmission and so it'll feel like it! It'll make the whole thing rev a load easier and it'll feel more 'alive'. Worth doing in conjunction with a clutch change to save on the labour costs too. I believe the EMB is universal as it has various dip switches on it to set it up for the correct engine type, but for both piggybacks you'll need the correct wiring looms unless you fancy hacking into the stock loom (do-able, but a PITA to put back when it comes to sell the car).This is what you really want before you start hacking anything: I had one myself and they're brilliant. ££££ 