You need boost if you want a chance in hell. I'd probably boost the 2.5L you have just for the sake of cost/reward.
Swapping a M3 motor in your car will likely cost at least 5K in labour plus the cost of labour (assuming its even possible, which i'm not saying it is)
hid lights hid kits
Hot: 2001 Estoril M Roadster
ZCP 19's, ZHP knob, JL 8W3
Cold: 2002 TiAg M3 6mt
ZCP 19's, ZHP knob, GROM, OEM 18's,