Powerplant options and what not

For 25K for can have a brand new Carerra S 3.8 installed. For 10-15K you should be able to get a 3.4 or 3.6 depending. For 8K you could supercharge it. For 2-3K you could do the header/exhaust stuff. Dont bother with the exhaust stuff if your wanting lots of power later on and will go for the engine swap, Itd be a waste. I bet a member who has done a swap will tell you the best option due to their experience.