Lou,
Very interesting model. What is the price of the kit? Are they available from a US distributor? What paint(s) will you be using to finish it?

All of the engines intended for the '109H were inline engines, but some used an 'annular radiator' (much like the Fw 190D and Ju 88A). None of the '109H airframes were 'racers', all were prototype fighters. The '209V-1 was not a 'racer', rather it was desighed to test high-speed flight and set speed records for propaganda.
More info:
From http://www.faqs.org/docs/air/avbf1092.html :
"* The "Bf-109H" was a high-altitude fighter ( "Hochleichtungsjaeger" ), featuring extended wings, a pressurized cockpit, and high-altitude engine fits, built in response to an RLM requirement issued in early 1943.

At first, the Bf-109H was concieved as basically a Frederick with wing inserts to provide extended span for high-altitude operation. The wing inserts had the incidental effect of moving the main landing gear outward, giving the aircraft a wider ground track.

However, this concept was abandoned as it could not meet RLM requirements. Messerschmitt then suggested that their new "Me-209H" fighter, then in development and discussed in more detail later, could do the job. The Me-209H was to have a new DB-628A or DB-603A turbocharged engine for high-altitude operation, but delivery of the Me-209-II was not expected until 1944. As an interim measure, the RLM ordered Messerschmitt to go ahead with the Bf-109H and redesign it for use with the new engines.

A Gustav, designated "Bf-109-V49", had already been fitted with a mockup of the DB-628A as part of the Me-209-II program, and so it was a straightforward step to install an operational DB-628A in another Gustav for Bf-109H flight tests as the "Bf-109-V50". While this aircraft was undergoing trials, a third Gustav was fitted with both the DB-628A and the extended wings.

While Messerschmitt worked on Bf-109H prototypes with the DB-628A engine, they also built of up a batch of "Bf-109H-0" fighters for engineering tests and "Bf-109H-1" fighters for field evaluation, all modified from Fredericks and powered by the more conventional DB-601E engine with GM-1 nitrous oxide boost.

The Bf-109H-1s were evaluated by the Luftwaffe in France in early 1944. The trials went well, except for the fact that the aircraft demonstrated an unhealthy wing flutter in dives. Tests were conducted on some of these aircraft back in Augsburg, and in April 1944 one lost a wing during a dive.

This apparently stalled the program, which was then presently cancelled in favor of the Focke-Wulf Ta-152H. A number of additional H-series subvariants were considered but never reached prototype stage."

More:
http://www.xs4all.nl/~tozu/me109/family/109H.htm

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