1. Cg10 pistons are straight swap onto cg13 conrods other than that there's no need to replace anything else
2. Pre 98 1.0 gearbox is different to post 98 (facelift) box so you'll be running the 1.0 flywheel and clutch which means a 160mm pressure plate, this restricts the tuning potential as only hold up to around 100-110 bhp, the 1.3 clutch and flywheel have different input shaft splines to pre facelift 1.0.
so ideally you want a 1998 on 1.0 flywheel and box on the 1.3 engine this will give you a 180mm clutch pressure plate that can handle a bit more power and a lighter flywheel than the 1.3 version.
3. Cg10 Ecu works fine.
4.other than crank seals, gaskets and the clutch you should be able to replace anything else as and when required.
5. Janspeed exhaust or similar and a good intake system is a good start. Cams if you are wanting to go further with it.
