2.0 16V swap to 1.8T

MK2 SEAT Ibiza runs a MK3 Golf subframe with MK2 Golf wishbones, so fitment wise its the same as a mk2/3 golf swap. if you can find a MK3 SEAT Ibiza these obviously are the very best donor for you, the downpipe will fit and I guess the rest of the exhaust will too? the wiring loom will still need adapted to suit your car, or I guess maybe the whole loom would fit? Not sure how close the MK2 and MK3 are in terms of wthe wiring routes in the car and thru the bulkhead, but I would count on at least some modification.

The MK2 Ibiza has a CE2 fusebox, so you can use this thread for MK4 loom conversion:
https://clubgti.com/forums/index.ph...install-faq-now-with-added-dieselness.267196/

MK3 Ibiza is totally different to mk2 and mk4, this thread should help if you get a MK3 Ibiza donor and keep MK2 Ibiza fusebox:
https://clubgti.com/forums/index.ph...-general-fusebox-plug-reference-guide.285928/

if you go for a mk4 engine then a conversion downpipe would be needed same as mk2/3 golf, and a larger bore exhaust probably. the ibiza has a 2.25" exhaust iirc, usually people go for 2.5 or 3" depending

as for what engine to get, have a read here:
http://clubgti.com/forums/index.php?threads/decoding-the-bam-hype.286688/

 

forgot to mention, since you have 2.0 16v you already have the right engine brackets and the ABF gearbox can work well for 20v swaps though it depends what sort of figures you're aiming for.

the 5 speed 20v box will fit fine as well if you prefer it, usually will have to swap the flanges over from the abf gearbox as 20v are 108mm. if its a 6 speed box theres a lot more work involved so unless you're really desperate I would forget that and stick with abf box

 

yeah the basic engine block is the same mk4 golf and mk3 ibiza, so either will drop in just fine. you can swap heads/turbo/inlet/injectors/etc to suit whatever plan you have, see the 'bam hype' thread for more in-depth analysis on this subject

if you get an ibiza donor it has an 02j gearbox with 100mm flanges so will bolt in, mk4 5 speed 02j gearbox will be 108mm so swap the 100mm flanges off the ABF 02A gearbox or use the complete abf gearbox whichever you prefer

 

AGU is early MK4 with drive by cable, AUM/AUQ later MK4 with drive by wire. BAM is the Audi TT lump which everyone wants as it has the most power 'out of the box' plus there are various myths floating about regarding 'forged bottom ends' and such.

But you can tune any 20v to the same levels with the right kit of parts and someone who knows how to map it, even an AGU. This can be done with the stock ecu, harder to find a willing mapper granted, or you fit later ecu and wiring at the same time you put the AGU into the car which would require various sensor, turbo, injectors, throttle body etc to complete but it's all bolt on stuff. This is a choice to make now before you build the wiring loom, as the AGU has totally different ECU plugs to the later AUM/AUQ/BAM/etc engines. So if you change later on it would mean making another wiring loom.

When it comes to choosing a way forward, if you plan to put a lot of upgrades in place to increase your power & torque, the very first thing to do is find a local mapper who can take care of the ECU for you. Listen to their advice, and build your engine accordingly. If you want to find a standard engine and just chuck it in and go, then it doesn't matter too much what you pick. Just be mindful of cupracraigs comments on the ECU if you have future upgrades in mind.

when it comes to the DBW ECU there are lots to choose from, and they're not all the same. the ibiza ecu for example is a narrowband type, the mk4 ecu are mostly wideband. (narrow and wideband refers to the main lambda sensor found before the cat) some have variable valve timing and some dont, the highest output ones also have exhaust gas temp sensors as well. so try to get a complete package so you know it all works together. even better if you can get one which is known to run then I would advise fitting it to the car as it is, dont mess about with anything till its running properly. nothing worse than trying to put together a total mongrel engine out of various parts then trying to figure out is it a wiring fault, a sensor fault, an ecu fault, or a mapping fault when it doesn't run

wiring wise some of the same codes of ecu have slightly different loom setups depending how old they are as well, so if you do end up mixing and matching parts be sure to post up what you find on here so we can ID everything you have.

There's a lot of detail in the BAM hype thread linked above to help you understand the various engines on offer, and where they come from