Steering light at speed?
Get it lowered!!! Mines down 40mm at the front (bit more at the back) and it's as solid as a rock at 130mph (yes..... on the autobahns to Nurburgring before you say owt..) The 17" wheels help no end too. I put on my spare set of STD prop 15" alloys last weekend to see how it feels and I hate it! Bit more comfy about the pot holes, but cornering and top end is horrible! 17's are going back on ASAP!
Nothing to "cure" the gearbox crunch, just re-engage the clutch and try again, Just how the IB5 'box is made unfortunately
EDIT: Girlfriend (also got a puma) recommends getting your tracking/balancing checked as well as your bushes (replace with powerflex if they're shot) as this helped her's no end at "speed"