hate to be a downer but this isnt the car you want to be modding if you have no budget. its all mercedes underneath and with little aftermarket support parts arent cheap. cai, pulley and tune will set you back close to 2k$ lsd another 1400$ exhaust another 800$ see what i mean?

best advice woud be decide what you want the power for. ie: autocross, road racing, drag racing. then form a plan based on the searches from here of what you want to do. then hunt surf and pray your the first to buy the used items that pop up or save hard and buy them new. either way get ready for a ride!

as for outside the forum needswings and eurocharged are about it. some folks have custom parts made but again it isnt cheap. dont forget suspension also gets the power to the ground and datalogging helps to know what the engine is doing. at 30k$ for a new engine you dont want to lunch a piston