The First-gen Vibe GT was actually a pretty sporty little car. Like many boneheaded-GM decisions, you could not get the big motor with the 5-speed, but the manual was still the way to go for maximum smiles. Lowering and adding some rubber is the ticket for fun at the autocross. They are dirt-cheap and pretty reliable and should fit a Tuba.
A little out of the box thinking, but the SX4 can be found with a stick and AWD and while no autocross champ, they could be a lot of fun as a first car, especially in the snow belt. Fitting a tuba might require KY however.
The Kia Soul is a great little box, but it is the antithesis of an enthusiasts car. Only car with a manual I ever drove that HATED to downshift, just refused to go into second under any circumstance. The throws are longer than a box truck and the clutch is unpredictable. Perfectly acceptable for calm driving, but turn it up and the Soul protests loudly. NO ROOM for a tuba as well, even with seats down.
The SAAB 900 (look for an SPG or Viggen) has a massive rear hatch that can actually swallow a tuba. I would have killed for this as a first car; somehting different and unique, good handling, practical, oddball. I have no idea about reliability however, my guess is they are either tanks or nightmares.
If it were MY kid, I would go Mazda 3. I loved the Mazdaspeed 3 of this gen, and the regular version is not much different. Loose the big power that will get him in trouble, but keep the tight chassis and great handling. This thing can kill it at the autocross and haul a tuba, probably.
The Breadvan Civics never got much love, which means you might be able to get one cheap, and they might fit the hardware. Certainly reliable and good on gas.
And finally, he's been a good kid man. Get him a Z3M Coupe dad!
