Welcome. First give an estimate of you budget for this car over say 1-1.5 years as knowing this will make it easier so you don't redo anything. Jefasold has the right idea for turning the stock pulley down as you retain all of it's strength and fit. I would think turning the stock pulley to 67mm should be safe but ask that here. Being in Bulgaria you would need to get your hands on a spare pulley and the shop Jim(Jefasold) knows well-address and it is on this forum so search. You can get the pulley turned for under $100. No fuel mods needed. Best bang for the buck. For a cold air intake you could do a do-it-yourself version or get the single unit sold by Rob at needswings.com The dual assemble looks better but is overkill, the single will flow enough.
Knowing the budget will help as some of the mods are costly. Eurocharged.com can email you a tune when you are ready. usually they sell that 65mm pulley referenced here with a tune for around $700. Sweet