Engine swop is really the best choice.
Cheapest options: (click on engine codes for engine performance stats)
Get a
Z18XE: Engine is straight fit, even fits on standard transmission (and yes the transmission can easily handle it). You only need a bigger radiator, need 2 replace the 2 heater pipes with u-bend pipes and need the ECU + Key set from the Z18XE engine or get after market ECU. Can be done for around R10K but expect to pay at least R15K if you have it done. Engine can only be had from Zafira B (locally) but usually the engine is imported because they weren't common here.
That should give you a 7 seconds to 100 performance. Aircon everything can be kept and if you fitted the larger radiator it'll be as reliable as standard.
Next option:
C20XE: This one you need an extra engine mounting, another transmission (GetRag F20 or F23), standard C20XE management, bigger radiator, different side shafts, so many things to name but it has been done plenty (no need to cut or anything like that, everything is just straight replace from Opel Kadett or Astra F) and many mechanics can do it (PM me if you want me to set you up with someone). It'll cost around R20K at least. Some people will say you can keep aircon, others not. This engine is available as an import and local. Locally it was used in the Opel Kadett GSi 16V S (commonly known as the SuperBoss) and also the Opel Kadett GSI 16v (known as BigBoss) and finally the Opel Monza 2.0 16v
Next option:
X30XE: This one will probably cost around R25K and it is a V6 3.0L from cars like the Isuzu Double Cab 3.0 Petrol. Drinks petrol but pretty much same procedure as C20XE but it isn't done much so it'll cost more because there are fewer mechanics that do it. But still you don't need to cut or whatever, only need extra mounting and replace a bunch of things. So say around R25-30K. Keeping air condition not an option.
Next option:
C20LET: This is the engine from the Astra 200tS. Pretty much the same procedure as doing a c20XE but the engines are expensive and rare so expect to many rands.
Fastest option:
C20XE (see above) with a Turbo: There are many of these out there, the most powerful I've seen outputs around 300kW at the wheels (the guy who owns it is known as CorsaNostra on the OpelOwnersForum). He is commonly at racing events but his setup cost him quite a bit but his car is 10 second quarter mile type car. Output can be anything from 150kW to 300kW as I said and it is fairly reliable depending who builds it, but all the options above are stock standard options and therefore they are VERY reliable whereas this could be less reliable because you need someone who really knows their stuff.
As for is it worth it?
Not sure, the car will be fast. A C20XE Corsa Lite will be faster in a straight line than a VW Golf GTi but it will definitely not be as luxurious and it can be very dangerous (you will have plenty of torque steer and wheel spin). But at the same time it can be fun to drive.
To answer the question, yes it is worth it if you want something fun and don't mind a rough and ready type racer that is a bit dangerous but if you want safe and luxurious get another car.
For example a Corsa with a c20xe engine will very quickly run off it's clock (eg. past 220km/h) and goes to around 250km/h, not exactly safe in a Corsa Lite. Corsa Lite with a Turbo C20XE is very dangrious, few people on the OpelOwnersForum have gotten killed (yeah, no joke, hitting trees and such because of overpowering torque steer and general wheel spin). I was in one and was driven in a straight line and it had wheel spin at 200km/h and it felt like a plane taking off, seriously feels unsafe
and that thing pretty much could hit ~270km/h before it ran out of RPM.
Some pics:
Z18XE Corsa
C20XE Corsa
C20LET Corsa
