I suggest you do a LOT of research.
The "chips" are usually a glorified resistor, which tricks the engine into thinking it is cold, therefore chucking more fuel in. All it will do is damage your engine.
As for a turbo you need usually need to strip the engine uprate pistons etc, add an inter cooler, after market management (which is close to £600 on it's own), get it professionally mapped and set up, new exhaust system and then with any conversion like that, you would have to upgrade the suspension and the brakes.
If your mate can do all that for £600 he is an absolute legend. Although I tend to think he is full of that stuff that comes out of a cow's !Removed!.