Michael, here's my take on your situation.
If you're going to purchase a Spyder, then build a big engine. Believe me, you'll be much happier. Many competent engine builders are out there, you just have to look. Go out and purchase a copy of "Hot VW's" or SandSport Magazine. Each has a plentiful number of engine builders.
Most of us that have Spyder have a minimum of 2,000 cc's. In my case, I have a 2165cc engine (94mm pistons and a counterweighted 78mm crank) In addition, I have ported and polished heads, modified engine case, beefed up rods, a modified cam, better rocker arms and an industrial strength clutch. All fed through twin 2 barrel 44mm Weber Carbs.
A stock VW engine consists of 85.5 mm pistons and a non-counterweighted 69 mm crank, being fed from a small 1 barrel carb for a total of 1,584 cc's
Stroke (longer crank) adds torque and more HP. Thats why Porsche designed the 356 and 912 engine with a 74 MM crank and 83 mm pistons for a total of 1601 cc's. These engines also had twin 2 barrel carbs.
Modify the case for added strength, add an additional thermostatically controlled oil cooler, use a "late" doghouse fan shroud with a "new" oil cooler, a welded and balanced fan, cut the case for "full flow", add an external oil filter, add a slim line oil sump and build at least a 2.1 liter engine and you'll be MUCH happier.
While you're at it, don't skimp on the transmission. Personally, at the minimum, I'd recommend a side plate, and a "super dif" You can alter the gear ratio's but I'd run the stock 4th gear. (.89)
I use a 3.88 to 1 ring and pinion due to it's strength over an early 4.12 and at 3,000 RPM's, running the most common rear size tire (205/60/15) my speed is 63 MPH. A 4.12 at 3,000 is 60 MPH. A 3.44 at 3000 is 71 MPH. (In my opinion, the 3.44 R & P is too slow for a modified VW engine) (remember, cooling comes from engine speed, but that's tricky, the faster you go, the more cooling you need, the slower you go, the less cooling required
speed = heat)
build a killer engine and you'll smoke Corvettes, Porsche's Camaro's and Mustangs up to about 65 MPH.
A well built engine performance should see 60,000 trouble free miles if driven properly and maintained with care.