looking to upgrade my stock s60 for cheap, thoughts?

 

really depends on your budget. for $500 or so you can get the ECU tuned to a stage 1. After that you can decide on a 3 inch downpipe or a turbo upgrade/rebuild - again budget another $500. Other engine money would be spent on making sure all the tubing etc is in good shape. I'd then turn attention to suspension parts. First is wheels/tires. 17s with 235/45s are pretty meaty and generally available at a fair price. You can also find OEM or after market rims in a 7.5x17 ET49 to fit. Budget about 500 for the tires (assuming you don't go top of the line) and 750 to 1000 for the rims. Next would be shocks/struts - A full kit of Bilsteins is in the 500 range gain (not counting install). I'd go with HD stabilizer bars next budget 300-400, and perhaps a strut tower brake. Finally you should shop for brake upgrades - you can start with ceramic pads and slotted rotors for $250. Big brake kits are available as well. After that, there's a diminishing return on cost/benefit but there's a lot of bits to be had - bigger injectors/boost controllers and so on...